This document summarizes a technical report on a compact, low-cost spatial-pattern diversity antenna system for mobile devices operating at 2.45GHz. The proposed antenna consists of two sets of passive arrays (A1 and A2), each with a probe-fed planar inverted-F antenna (PIFA) and an open-circuited PIFA (PILA). Placement of the PIFA and PILA introduces strong mutual coupling that splits the PIFA's resonant frequency into two coupled modes. Introducing a slit between the PIFA and PILA modifies the coupling and causes the PILA to act as a director, enhancing radiation in one direction. Variations to the slit width affect the resonant frequencies and directivity of
The document discusses and compares the performance of various antenna designs through return loss/VSWR plots and radiation patterns sourced from several research papers. Key findings include that bicone and monocone antennas have bandwidths over 7 GHz but are difficult to fabricate. A helix antenna with a capacitive coupling has the best performance of the helix designs with a bandwidth of around 4 GHz. Square planar monopole antennas with trident or double feeding strips have bandwidths of around 10 GHz. Vivaldi antennas and circular/elliptical dipole antennas also achieve bandwidths greater than 9 GHz. LPDA and monopole antennas have more varied performance depending on specific dimensions.
L shaped slot loaded semicircular patch antenna for wideband operation ijwmn
This document summarizes a research paper that analyzes a dual-band semicircular microstrip patch antenna loaded with an L-shaped slot. Introducing the L-shaped slot creates two resonant frequencies for wideband operation. Parametric studies using MATLAB and HFSS simulation software show that the slot dimensions affect the lower resonance frequency more than the upper frequency, while the notch dimensions have more impact on the upper frequency. Radiation patterns are presented for both resonance frequencies, demonstrating dual-band behavior. The proposed antenna design achieves size reduction compared to other techniques for obtaining multiple bands in microstrip antennas.
Design of an improved transistor performance for rf application using bipole3mohamed albanna
This document describes a simulation of a bipolar junction transistor for radio frequency applications using the Bipole3 device simulator. The simulator was first calibrated using physical parameters measured from the transistor. Then, the transistor's performance was simulated. The simulation aimed to improve the transit frequency fT, which is an important figure of merit. However, improving fT can negatively impact other parameters like base resistance Rb and early voltage VA, which are important for RF performance. The simulation examined doping concentration and profile adjustments to increase fT while maintaining good Rb and VA.
This document discusses GPS passive patch antennas from Maxtena. It provides an overview of microstrip patch antennas and their advantages/disadvantages. It then discusses Maxtena's ceramic patch antennas, including their sizes, performance characteristics like efficiency and gain, and how performance is affected by the size and position of the ground plane. It recommends using Maxtena's tuning kits to match the antenna's resonant frequency when installed in a specific device configuration due to shifts caused by the ground plane.
Proposed P-shaped Microstrip Antenna Array for Wireless Communication Applica...TELKOMNIKA JOURNAL
In this paper a P-shaped microstrip antenna array is proposed for X-band applications in the
frequency range (8.1567-9.3811) GHz .The gain obtained in this frequency range is about 8.305 dBi.
The reflection coefficient is less than - 10 dB in the above frequency range. The simulation results were
obtained for the optimum parameters using the CST software while the practical test was carried out using
Vector Network Analyzer (VNA). The microstrip antenna was manufactured using FR-4 substrate with
relative dielectric constant of 4.3 and loss tangent 푡푎푛 훿 = 0.002.The simulation and practical results were
compared. The size of the antenna array is (33 × 70 × 1.6) 푚푚3. This array is suitable for satellite
communication, radar application.
This document discusses patch antennas. It describes the basic structure of a patch antenna, which consists of a radiating metallic patch on a dielectric substrate with a ground plane on the other side. Patch antennas radiate a linearly polarized wave and have a very low profile. Their primary limitation is narrow bandwidth, which is typically less than 5% for single-substrate designs. Common patch antenna geometries include rectangular and circular shapes to generate different beam patterns.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
Design of Star-Shaped Microstrip Patch Antenna for Ultra Wideband (UWB) Appli...ijwmn
The document describes the design and simulation of a star-shaped microstrip patch antenna for ultra-wideband applications from 3.9GHz to 22.5GHz. The antenna structure and parameters are presented, including the substrate properties and feed line dimensions. Simulation results show the antenna achieves impedance matching across its operating bandwidth, with gains between 1.95-5dB and directional radiation patterns depending on frequency. A parametric study examines the effects of shifting the feed line position and changing the ground plane length on impedance bandwidth.
The document discusses and compares the performance of various antenna designs through return loss/VSWR plots and radiation patterns sourced from several research papers. Key findings include that bicone and monocone antennas have bandwidths over 7 GHz but are difficult to fabricate. A helix antenna with a capacitive coupling has the best performance of the helix designs with a bandwidth of around 4 GHz. Square planar monopole antennas with trident or double feeding strips have bandwidths of around 10 GHz. Vivaldi antennas and circular/elliptical dipole antennas also achieve bandwidths greater than 9 GHz. LPDA and monopole antennas have more varied performance depending on specific dimensions.
L shaped slot loaded semicircular patch antenna for wideband operation ijwmn
This document summarizes a research paper that analyzes a dual-band semicircular microstrip patch antenna loaded with an L-shaped slot. Introducing the L-shaped slot creates two resonant frequencies for wideband operation. Parametric studies using MATLAB and HFSS simulation software show that the slot dimensions affect the lower resonance frequency more than the upper frequency, while the notch dimensions have more impact on the upper frequency. Radiation patterns are presented for both resonance frequencies, demonstrating dual-band behavior. The proposed antenna design achieves size reduction compared to other techniques for obtaining multiple bands in microstrip antennas.
Design of an improved transistor performance for rf application using bipole3mohamed albanna
This document describes a simulation of a bipolar junction transistor for radio frequency applications using the Bipole3 device simulator. The simulator was first calibrated using physical parameters measured from the transistor. Then, the transistor's performance was simulated. The simulation aimed to improve the transit frequency fT, which is an important figure of merit. However, improving fT can negatively impact other parameters like base resistance Rb and early voltage VA, which are important for RF performance. The simulation examined doping concentration and profile adjustments to increase fT while maintaining good Rb and VA.
This document discusses GPS passive patch antennas from Maxtena. It provides an overview of microstrip patch antennas and their advantages/disadvantages. It then discusses Maxtena's ceramic patch antennas, including their sizes, performance characteristics like efficiency and gain, and how performance is affected by the size and position of the ground plane. It recommends using Maxtena's tuning kits to match the antenna's resonant frequency when installed in a specific device configuration due to shifts caused by the ground plane.
Proposed P-shaped Microstrip Antenna Array for Wireless Communication Applica...TELKOMNIKA JOURNAL
In this paper a P-shaped microstrip antenna array is proposed for X-band applications in the
frequency range (8.1567-9.3811) GHz .The gain obtained in this frequency range is about 8.305 dBi.
The reflection coefficient is less than - 10 dB in the above frequency range. The simulation results were
obtained for the optimum parameters using the CST software while the practical test was carried out using
Vector Network Analyzer (VNA). The microstrip antenna was manufactured using FR-4 substrate with
relative dielectric constant of 4.3 and loss tangent 푡푎푛 훿 = 0.002.The simulation and practical results were
compared. The size of the antenna array is (33 × 70 × 1.6) 푚푚3. This array is suitable for satellite
communication, radar application.
This document discusses patch antennas. It describes the basic structure of a patch antenna, which consists of a radiating metallic patch on a dielectric substrate with a ground plane on the other side. Patch antennas radiate a linearly polarized wave and have a very low profile. Their primary limitation is narrow bandwidth, which is typically less than 5% for single-substrate designs. Common patch antenna geometries include rectangular and circular shapes to generate different beam patterns.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
Design of Star-Shaped Microstrip Patch Antenna for Ultra Wideband (UWB) Appli...ijwmn
The document describes the design and simulation of a star-shaped microstrip patch antenna for ultra-wideband applications from 3.9GHz to 22.5GHz. The antenna structure and parameters are presented, including the substrate properties and feed line dimensions. Simulation results show the antenna achieves impedance matching across its operating bandwidth, with gains between 1.95-5dB and directional radiation patterns depending on frequency. A parametric study examines the effects of shifting the feed line position and changing the ground plane length on impedance bandwidth.
The International Journal of Engineering and Science (IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Ferrite beads are passive devices that filter high frequency noise by becoming resistive over a certain frequency range. When combined with capacitors, they form a low-pass filter to further reduce power supply noise. However, improperly combining a ferrite bead and decoupling capacitor can lead to unwanted resonance below the bead's crossover frequency, amplifying noise instead of attenuating it. For example, a specific ferrite bead and ceramic capacitor combination exhibited unwanted resonance at around 2.5MHz. Adding an additional RC filter can help reduce unwanted resonance. Choosing a ferrite bead with low DCR can also help minimize voltage drops from current.
This document summarizes the design and simulation of a dual-band Y-shaped printed antenna for satellite communication. A conventional microstrip patch antenna was first designed with a resonant frequency of 9.8 GHz. A Y-shaped slot was then introduced to the patch, reducing the resonant frequency to 6.23 GHz and 9.56 GHz. The simulated slotted antenna achieved a size reduction of 52.02% compared to the conventional design, with gains of 4.69 dBi at 6.23 GHz and 4.18 dBi at 9.56 GHz. Radiation patterns for both frequencies showed 3dB beamwidths between 166-170 degrees. The dual-band slotted antenna design demonstrates potential for C-band and X
This document describes the design and simulation of a multiband patch antenna using a Pythagorean fractal structure. In the base antenna design, resonance is achieved at 8GHz. The first fractal iteration uses a Pythagorean triangle equation to modify the patch shape. In simulation, this first iteration achieves two resonances, at 8.2GHz and 9.2GHz, when fed by both a coaxial probe and microstrip line. While the radiation patterns are not perfectly broadside, radiation still occurs in the upper quadrant. The simple fractal structure provides a potential way to miniaturize antennas while achieving multiband performance.
Performance of Groundplane Shaping in Four-Element Dualband MIMO AntennaTELKOMNIKA JOURNAL
This work presents performance of groundplane shaping and its effect in four element dualband
multiple input multiple output (MIMO) antenna. This proposed four element dualband MIMO antenna
consists of four bowtie dipole antenna which operates at 1800 MHz (low frequency) and 2300 MHz (high
frequency). This proposed four element dualband MIMO antenna occupies a 270 x 210 x 100 mm3 of FR
4 substrate. We use four types of groundplane pattern i.e. full groundplane, cornered spatial groundplane,
crossed middle groundplane, and spiral groundplane. These various grounplane patterns influence the
performance of main parameters of dualband MIMO antenna. Cornered spatial groundplane pattern yields
a largest bandwidth (VSWR ≤ 2) 282 MHz or 15.24% of center frequency at low frequency. Full
groundplane pattern creates 135.2 MHz at high frequency. In addition, cornered spatial groundplane
pattern also generates a lowest VSWR that is valued 1.21 at both low frequency and high frequency. The
S parameters, basically both cornered spatial and full groundplane pattern produce a better return loss
than two others. All four groundplane patterns deliver equally a mutual coupling parameter.The last, this
proposed four element dualband MIMO with various groundplane patterns gives a good farfield properties
i.e. gain, radiation pattern, H-E field.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Printed Omnidirectional Access-Point Antenna for 2.4/5-GHz WLAN OperationSaou-Wen Su
A new design of the printed omnidirectional antenna for applications in 2.4/5-GHz dual-WLAN-band access points is proposed. The antenna consists of a conventional collinear antenna for 2.4 GHz operation and two U stubs for 5 GHz operation. The two U stubs are located near the points where the maximum currents at about 5.5 GHz occurring on the strips of the collinear antenna, and arranged back to back in the same phase for achieving better antenna gain. Detailed analyses of the U stub on the impedance matching over the 5 GH band is presented. A prototype with good omnidirectional radiation across the 2.4/5-GHz WLAN bands is demonstrated.
Pentagon and circular ring slot loaded rectangular microstrip monopoleIAEME Publication
The document describes the design and development of two pentagon and circular ring slot loaded rectangular microstrip monopole antennas (PCRSLRMA and PCCSLRMA) for quad-band and triple-band operation, respectively. The PCRSLRMA operates in four bands between 4-16 GHz while the PCCSLRMA operates in three bands. Both antennas exhibit omnidirectional radiation patterns. The PCRSLRMA achieves a maximum gain of 11.37 dB while the PCCSLRMA achieves 9.98 dB. The addition of the complementary circular ring slot in the PCCSLRMA enhances the bandwidth at each operating band compared to the PCRSLRMA. The proposed antennas have a simple
Comparative Study, Design and Performance Analysis of Wide Slot Antenna with ...IJMER
This document presents the design and simulation of a triangular wide slot antenna with a triangular patch feed. The antenna achieves an impedance bandwidth of 116% from 2.1 GHz to 7.9 GHz. Various parameters of the antenna design were analyzed through simulation to understand their impact on bandwidth, including patch length and width, feed gap width, and waveguide width. Sensitivity analysis showed that a patch length and width of 15 mm, feed gap of 2.5 mm, and waveguide width of 0.7 mm produced an optimized performance with stable radiation patterns across the operating band. The antenna demonstrates potential for applications requiring wide bandwidth such as WLAN, Wi-Fi, and WiMAX.
Fractal Reconfigurable Multiband Communicating Antenna for Cognitive RadioIOSR Journals
This document summarizes a research paper that proposes a novel fractal reconfigurable multiband antenna design for cognitive radio applications. The antenna structure combines a triangular fractal patch with parasitic elements and PIN diode switches. The switches can be activated or deactivated to change the electrical lengths and alter the current flow, dynamically changing the antenna's resonance frequencies. Simulation results show the antenna achieves frequency reconfigurability, operating at different resonant frequencies depending on the states of the switches. The proposed antenna design provides a compact, multiband solution that is well-suited for cognitive radio applications.
An Optimization Of Circularly Polarized Knight’s Helm Shaped Patch Antenna Fo...IOSR Journals
This document summarizes the optimization of a circularly polarized knight's helm shaped patch antenna for ultra wideband applications. The proposed antenna was designed on an FR-4 substrate with a double slotted rectangular patch tapered from a 50-ohm feed line and a partial ground plane. Simulation results showed the antenna achieved an impedance bandwidth from 3.04GHz to 10.96GHz with return loss below -10dB and VSWR less than 2 throughout the band. Key dimensions of the antenna are provided in a table.
Compact Rectangular Slot Microstrip Antenna with Band-Notched Characteristics...jmicro
n this paper, we present an offset microstrip-fed ultraw
ideband antenna with band notch
characteristics.The antenna structure consists of rectangular r
adiating patch and ground plane with
rectangular shaped slot, which increases impedance bandwidth upto 1
17.73%(2.9-11.2GHz).A new
modified U slot is etched in the radiating patch to create band-
notched properties in the WiMAX (3.3-
3.7GHz) and C-band satellite communication (3.7-4.15GHz).Further
more, parametric studies have been
conducted using EM simulation software CADFEKO suite(7.0) and
optimized with stable radiation pattern
which satisfied UWB requirement for VSWR<2.A prototype of ante
nna is fabricated on 1.6mm thick FR-4
substrate with dielectric constant of 4.4 and loss tangent of 0.02
.The designed antenna exhibits
bidirectional and omni directional radiation patterns along E and
H-plane with stable gain and efficiency
over entire operating band except notch frequency band. Simulated res
ults are in good agreement with the
measured results of the proposed antenna which makes it a good
candidate for UWB application.
The document analyzes economic and demographic trends in 20 major Indian cities. It finds that the top 20 cities account for less than 10% of India's population but over 30% of national income. Certain cities like Surat and Kanpur are experiencing especially fast income and economic growth. The analysis also projects that by 2016 over half of Indian households will be considered middle class, and the high-income segment will triple nationwide and quadruple in fast-growing boomtown cities. Middle class ownership patterns of cars and homes vary significantly across different types of cities.
This document provides information about career guidance resources available on a website, including a psychometric test to identify strengths and help with career choice, career counseling, contests and games. It describes a 2D game called "Mysterious Minds" that has different levels and allows players to choose an avatar and find animals and trivia in various settings. Contact details and social media links are also listed.
This document provides an overview of BMW including its history, products, competitors, and financial report. BMW was founded in 1913 as Rapp Motorenwerke and produced aircraft engines. It was later taken over by Franz Josef Popp in 1918 and renamed BMW. BMW manufactures motorcycles, cars including the 1, 3, 5, 6, 7 series and Jeeps. Its main competitors are Mercedes, Audi, Volkswagen, and Volvo. BMW recently reported its best first quarter with 383,000 cars sold and a net profit of 1.21 billion euros, with growth of 20.8% for BMW, 22.9% for Mini, and over 100% for Rolls Royce.
Company Presentation Of Jobmet En 2011 11Xingqi_Ye
Jobmet is a Chinese HR recruiting company founded in 2005 with over 350 staff across 12 offices in China. They provide innovative recruiting solutions to clients using a database of over 22 million candidates, career consultants, and recruiting technology. Their main services include executive search, recruitment process outsourcing, talent market research, and talent database management.
The International Journal of Engineering and Science (IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Ferrite beads are passive devices that filter high frequency noise by becoming resistive over a certain frequency range. When combined with capacitors, they form a low-pass filter to further reduce power supply noise. However, improperly combining a ferrite bead and decoupling capacitor can lead to unwanted resonance below the bead's crossover frequency, amplifying noise instead of attenuating it. For example, a specific ferrite bead and ceramic capacitor combination exhibited unwanted resonance at around 2.5MHz. Adding an additional RC filter can help reduce unwanted resonance. Choosing a ferrite bead with low DCR can also help minimize voltage drops from current.
This document summarizes the design and simulation of a dual-band Y-shaped printed antenna for satellite communication. A conventional microstrip patch antenna was first designed with a resonant frequency of 9.8 GHz. A Y-shaped slot was then introduced to the patch, reducing the resonant frequency to 6.23 GHz and 9.56 GHz. The simulated slotted antenna achieved a size reduction of 52.02% compared to the conventional design, with gains of 4.69 dBi at 6.23 GHz and 4.18 dBi at 9.56 GHz. Radiation patterns for both frequencies showed 3dB beamwidths between 166-170 degrees. The dual-band slotted antenna design demonstrates potential for C-band and X
This document describes the design and simulation of a multiband patch antenna using a Pythagorean fractal structure. In the base antenna design, resonance is achieved at 8GHz. The first fractal iteration uses a Pythagorean triangle equation to modify the patch shape. In simulation, this first iteration achieves two resonances, at 8.2GHz and 9.2GHz, when fed by both a coaxial probe and microstrip line. While the radiation patterns are not perfectly broadside, radiation still occurs in the upper quadrant. The simple fractal structure provides a potential way to miniaturize antennas while achieving multiband performance.
Performance of Groundplane Shaping in Four-Element Dualband MIMO AntennaTELKOMNIKA JOURNAL
This work presents performance of groundplane shaping and its effect in four element dualband
multiple input multiple output (MIMO) antenna. This proposed four element dualband MIMO antenna
consists of four bowtie dipole antenna which operates at 1800 MHz (low frequency) and 2300 MHz (high
frequency). This proposed four element dualband MIMO antenna occupies a 270 x 210 x 100 mm3 of FR
4 substrate. We use four types of groundplane pattern i.e. full groundplane, cornered spatial groundplane,
crossed middle groundplane, and spiral groundplane. These various grounplane patterns influence the
performance of main parameters of dualband MIMO antenna. Cornered spatial groundplane pattern yields
a largest bandwidth (VSWR ≤ 2) 282 MHz or 15.24% of center frequency at low frequency. Full
groundplane pattern creates 135.2 MHz at high frequency. In addition, cornered spatial groundplane
pattern also generates a lowest VSWR that is valued 1.21 at both low frequency and high frequency. The
S parameters, basically both cornered spatial and full groundplane pattern produce a better return loss
than two others. All four groundplane patterns deliver equally a mutual coupling parameter.The last, this
proposed four element dualband MIMO with various groundplane patterns gives a good farfield properties
i.e. gain, radiation pattern, H-E field.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Printed Omnidirectional Access-Point Antenna for 2.4/5-GHz WLAN OperationSaou-Wen Su
A new design of the printed omnidirectional antenna for applications in 2.4/5-GHz dual-WLAN-band access points is proposed. The antenna consists of a conventional collinear antenna for 2.4 GHz operation and two U stubs for 5 GHz operation. The two U stubs are located near the points where the maximum currents at about 5.5 GHz occurring on the strips of the collinear antenna, and arranged back to back in the same phase for achieving better antenna gain. Detailed analyses of the U stub on the impedance matching over the 5 GH band is presented. A prototype with good omnidirectional radiation across the 2.4/5-GHz WLAN bands is demonstrated.
Pentagon and circular ring slot loaded rectangular microstrip monopoleIAEME Publication
The document describes the design and development of two pentagon and circular ring slot loaded rectangular microstrip monopole antennas (PCRSLRMA and PCCSLRMA) for quad-band and triple-band operation, respectively. The PCRSLRMA operates in four bands between 4-16 GHz while the PCCSLRMA operates in three bands. Both antennas exhibit omnidirectional radiation patterns. The PCRSLRMA achieves a maximum gain of 11.37 dB while the PCCSLRMA achieves 9.98 dB. The addition of the complementary circular ring slot in the PCCSLRMA enhances the bandwidth at each operating band compared to the PCRSLRMA. The proposed antennas have a simple
Comparative Study, Design and Performance Analysis of Wide Slot Antenna with ...IJMER
This document presents the design and simulation of a triangular wide slot antenna with a triangular patch feed. The antenna achieves an impedance bandwidth of 116% from 2.1 GHz to 7.9 GHz. Various parameters of the antenna design were analyzed through simulation to understand their impact on bandwidth, including patch length and width, feed gap width, and waveguide width. Sensitivity analysis showed that a patch length and width of 15 mm, feed gap of 2.5 mm, and waveguide width of 0.7 mm produced an optimized performance with stable radiation patterns across the operating band. The antenna demonstrates potential for applications requiring wide bandwidth such as WLAN, Wi-Fi, and WiMAX.
Fractal Reconfigurable Multiband Communicating Antenna for Cognitive RadioIOSR Journals
This document summarizes a research paper that proposes a novel fractal reconfigurable multiband antenna design for cognitive radio applications. The antenna structure combines a triangular fractal patch with parasitic elements and PIN diode switches. The switches can be activated or deactivated to change the electrical lengths and alter the current flow, dynamically changing the antenna's resonance frequencies. Simulation results show the antenna achieves frequency reconfigurability, operating at different resonant frequencies depending on the states of the switches. The proposed antenna design provides a compact, multiband solution that is well-suited for cognitive radio applications.
An Optimization Of Circularly Polarized Knight’s Helm Shaped Patch Antenna Fo...IOSR Journals
This document summarizes the optimization of a circularly polarized knight's helm shaped patch antenna for ultra wideband applications. The proposed antenna was designed on an FR-4 substrate with a double slotted rectangular patch tapered from a 50-ohm feed line and a partial ground plane. Simulation results showed the antenna achieved an impedance bandwidth from 3.04GHz to 10.96GHz with return loss below -10dB and VSWR less than 2 throughout the band. Key dimensions of the antenna are provided in a table.
Compact Rectangular Slot Microstrip Antenna with Band-Notched Characteristics...jmicro
n this paper, we present an offset microstrip-fed ultraw
ideband antenna with band notch
characteristics.The antenna structure consists of rectangular r
adiating patch and ground plane with
rectangular shaped slot, which increases impedance bandwidth upto 1
17.73%(2.9-11.2GHz).A new
modified U slot is etched in the radiating patch to create band-
notched properties in the WiMAX (3.3-
3.7GHz) and C-band satellite communication (3.7-4.15GHz).Further
more, parametric studies have been
conducted using EM simulation software CADFEKO suite(7.0) and
optimized with stable radiation pattern
which satisfied UWB requirement for VSWR<2.A prototype of ante
nna is fabricated on 1.6mm thick FR-4
substrate with dielectric constant of 4.4 and loss tangent of 0.02
.The designed antenna exhibits
bidirectional and omni directional radiation patterns along E and
H-plane with stable gain and efficiency
over entire operating band except notch frequency band. Simulated res
ults are in good agreement with the
measured results of the proposed antenna which makes it a good
candidate for UWB application.
The document analyzes economic and demographic trends in 20 major Indian cities. It finds that the top 20 cities account for less than 10% of India's population but over 30% of national income. Certain cities like Surat and Kanpur are experiencing especially fast income and economic growth. The analysis also projects that by 2016 over half of Indian households will be considered middle class, and the high-income segment will triple nationwide and quadruple in fast-growing boomtown cities. Middle class ownership patterns of cars and homes vary significantly across different types of cities.
This document provides information about career guidance resources available on a website, including a psychometric test to identify strengths and help with career choice, career counseling, contests and games. It describes a 2D game called "Mysterious Minds" that has different levels and allows players to choose an avatar and find animals and trivia in various settings. Contact details and social media links are also listed.
This document provides an overview of BMW including its history, products, competitors, and financial report. BMW was founded in 1913 as Rapp Motorenwerke and produced aircraft engines. It was later taken over by Franz Josef Popp in 1918 and renamed BMW. BMW manufactures motorcycles, cars including the 1, 3, 5, 6, 7 series and Jeeps. Its main competitors are Mercedes, Audi, Volkswagen, and Volvo. BMW recently reported its best first quarter with 383,000 cars sold and a net profit of 1.21 billion euros, with growth of 20.8% for BMW, 22.9% for Mini, and over 100% for Rolls Royce.
Company Presentation Of Jobmet En 2011 11Xingqi_Ye
Jobmet is a Chinese HR recruiting company founded in 2005 with over 350 staff across 12 offices in China. They provide innovative recruiting solutions to clients using a database of over 22 million candidates, career consultants, and recruiting technology. Their main services include executive search, recruitment process outsourcing, talent market research, and talent database management.
Vidhya Srinivasan is seeking an enterprising career opportunity that allows her to utilize her 7 years of experience in sales, customer service, and human resources. She has a BA in English Literature and an MBA in Human Resources. Her relevant work experience includes positions at Net Vision Cybertech Ltd., Sutherland Global Services, Citibank, ICICI Lombard, and McKinsey & Co. Her key skills include sales, customer service, leadership, attention to detail, problem analysis, and troubleshooting.
— The Sierpinski fractal antenna has been analyzed
parametrically, and observed how its characteristics changing
with the variation of its different parameters. The input return
loss and input impedance have log periodic behavior that
characterizes the sierpinski monopole antenna as fractal
geometry. The band spacing and impedance matching have been
improved by using different scale factor and feeding methods.
Sierpinski monopole antenna for WLAN bands (2.4GHz and
5GHz) has been designed and simulated using Ansoft Hfss.The
operating frequencies of the proposed designs match with
IEEE802.11b (2.45GHz) and IEEE802.11a (5.20 GHz and
5.775GHz) standards which would allow WLAN operation.
This document describes the design, simulation, fabrication, and testing of a broadband discone antenna with an operating frequency range of 500 MHz to 1 GHz. The author theoretically designed the discone antenna by selecting design parameters like a 66 degree flare angle and 750 MHz operating frequency. Simulation in HFSS optimized the parameters, resulting in a 1 mm cone-disc gap and 76.25 mm disc diameter. A physical model was constructed and tested, with measured return loss crossing -10 dB around 890 MHz. While the simulated and measured operating frequencies were higher than the intended 750 MHz, the discone antenna design achieved the goal of operating over 500 MHz to 1 GHz.
In this paper, a dual frequency resonance antenna is analysed by introducing L-shaped slot in a
semi circular patch, different parametric studies have allows and the results in terms of return
loss and radiation pattern are given. It is observed that various antenna parameters are
obtained as a function of frequency for different value of slot length and width; it is easy to
adjust the upper and the lower band by varying these different antenna parameters. The coaxial
feed is used to excite the patch antenna. Theoretical results using Matlab are compared with the
simulated results obtained from Ansoft HFSS and shown to be in good agreement.
This document summarizes a research paper that proposes a new dual band-notched ultra-wideband antenna. The antenna uses a pair of bent dual-L-shaped parasitic branches attached to a circular slotted ground plane to create notched bands at 3.3-3.7 GHz for WiMAX and 5.15-5.825 GHz for WLAN. The lengths and positions of the branches determine the desired notch frequencies. Both simulated and measured results show good agreement and dual band-notched performance across the UWB band, validating the design concept.
This document summarizes a research paper that proposes a new dual band-notched ultra-wideband antenna. The antenna uses a pair of bent dual-L-shaped parasitic branches attached to a circular slotted ground plane to create notched bands at 3.3-3.7 GHz for WiMAX and 5.15-5.825 GHz for WLAN. The lengths and positions of the branches determine the desired notch frequencies. Both simulated and measured results show good agreement and validate the antenna's ability to achieve the dual notched bands over the ultra-wideband range.
This document summarizes a research paper that proposes a new dual band-notched ultra-wideband (UWB) antenna. The antenna uses a pair of bent dual-L-shaped parasitic branches attached to a circular slotted ground plane to create notched bands at 3.3-3.7 GHz for WiMAX and 5.15-5.825 GHz for WLAN. The lengths and positions of the branches were optimized to achieve the desired notch frequencies. Simulated and measured results showed good agreement and that the antenna has good radiation patterns and time-domain performance, making it suitable for modern UWB communication systems.
DESIGN OF TRIPLE-BAND CPW FED CIRCULAR FRACTAL ANTENNA IJCI JOURNAL
A novel miniaturized circular fractal antenna is designed by inscribing circular slot on rectangular ground plane and successively forming circular rings connected by semi-circles for circular-fractal patch. Novel modified Coplanar Waveguide (CPW) is used as feed for fractal circular patch. The analysis of parametric variations is performed by consecutive fractal iterations, varying the radius of inscribed circle of ground plane, slots and different ground plane configurations. To further enhance gain and radiation pattern a dual inverted L slots is included in ground plane. From the results it is evident that, the proposed fractal antenna possesses triple bands at 1.8GHz, 3.5GHz and 5.5GHz. These bands are used in Digital Communication Systems (DCS) (1.8GHz), IEEE 802.16d fixed WiMAX (3.5GHz) and IEEE 802.11a WLAN (5.5GHz) applications.
Design of Tripl-Band CPW FED Circular Fractal Antenna ijcisjournal
A novel miniaturized circular fractal antenna is designed by inscribing circular slot on rectangular ground
plane and successively forming circular rings connected by semi-circles for circular-fractal patch. Novel
modified Coplanar Waveguide (CPW) is used as feed for fractal circular patch. The analysis of parametric
variations is performed by consecutive fractal iterations, varying the radius of inscribed circle of ground
plane, slots and different ground plane configurations. To further enhance gain and radiation pattern a
dual inverted L slots is included in ground plane. From the results it is evident that, the proposed fractal
antenna possesses triple bands at 1.8GHz, 3.5GHz and 5.5GHz. These bands are used in Digital
Communication Systems (DCS) (1.8GHz), IEEE 802.16d fixed WiMAX (3.5GHz) and IEEE 802.11a WLAN
(5.5GHz) applications.
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This document describes a simulation of a bipolar junction transistor for radio frequency applications using the Bipole3 device simulator. The simulator was first calibrated with physical parameters and measurement data. Then, the transistor was simulated. Modifications were made to improve the transit frequency fT and other performance metrics. The simulations showed higher fT, current gain, and cutoff frequency fmax for the modified transistor design compared to the original design. Some parameter values had to be adjusted further to make the current gain simulations more realistic.
DUAL BAND F-ANTENNA FOR EUROPE AND NORTH AMERICAijwmn
A single antenna for multiple bands are always beneficial from the design point of view. Here a single antenna which is fundamentally inverted F antenna is used, the uniqueness of the design is that , it uses trap technique to produce dual resonance from a single inverted F antenna . The trap used to block the current due to some frequencies and passes the current contributed by other frequencies. So in short , this trap is like a RF filter which has some passband as well as stop band. This trap approach uses a LC network to achieve this design goal .The two bands of interest are 865-870 MHz and 902-928 MHz .. The challenge of this design is that the frequency separation of the two bands is very small. In this case, and also the extra section for low frequency band is too small. Then, the influence of trap LC component variation due to tolerance to the two resonant frequencies is big, and so it is difficult to achieve good in band return loss within the LC tolerance. This is the main difficulty of this design. This issue is resolved by placing the low band section away from the end of the antenna. The antenna is designed on FR4 substrate material having thickness of 1.6 mm and hence it is a low cost solution which could use in various commercial applications which follows these bands.
This document describes the design and characteristics of a dual-band antenna for WiMAX applications. The antenna consists of a U-shaped patch connected to a T-shaped stub, with two rectangular slots cut into the ground plane to reduce mutual coupling between the two ports. The antenna operates at 2.5 GHz and 5.5 GHz bands for WiMAX. Simulation results show that adjusting parameters like the length of the U-shaped patch and lateral patches can individually tune the resonance frequencies and bandwidths of the two bands. Measurements of the radiation patterns show omnidirectional behavior as expected. The compact dual-band antenna design achieves good performance for both wireless communication bands.
Low Profile Inverted-F-L Antenna for 5.5 GHz WiMAX ApplicationsIDES Editor
This paper presents a novel low profile inverted-FL
antenna (IFLA) for worldwide interoperability for microwave
access (WiMAX) applications by means of numerical
simulation. The antenna has compact size of 9×20 mm2 and
provides a wide bandwidth of 750 MHz (5150~5900 MHz) which
covers the 5.5 GHz WiMAX applications. Moreover it has very
high peak gain of 8.04 dBi with 1.38 dBi gain variation within
the 10 dB return loss bandwidth. The VSWR of the proposed
IFLA varies from 1.79849 to 1.91245 within the antenna 10 dB
return loss bandwidth. The antenna provides peak return loss
of -29.903 dB at 5.45 GHz and the input impedance of proposed
IFLA is 47.8595 Ω at 5.5 GHz.
Dual band microstrip antenna with slit load design for wireless local area ne...BASIM AL-SHAMMARI
This paper presents a design of dual frequency band operation nearly square patch antenna
for IEEE 802.11b,g (2.4Ghz-2.4835GHz) and IEEE 802.11a (5.15GHz-5.25GHz)by using a patch
antenna. The patch and ground plane are separated by a substrate; the radiating patch have two pairs
of orthogonal slits cut from the edge, this antenna has wide bandwidth in the frequency band of
(WLAN) and with a return loss ≤ −10 dB from 2.4 GHz to 2.48 GHz and from 5.12 GHz to 5.32
GHz exhibits circularly polarized far-field radiation pattern. The proposed antennas have been
simulated and analyzed using method of moments (MoM) based software package Microwave
Office 2009 v9.0. The results show that the antenna has dual-band frequency operation by using slit
load.
Dual band microstrip antenna with slit load design for wireless local area ne...BASIM AL-SHAMMARI
This paper presents a design of dual frequency band operation nearly square patch antenna
for IEEE 802.11b,g (2.4Ghz-2.4835GHz) and IEEE 802.11a (5.15GHz-5.25GHz)by using a patch
antenna. The patch and ground plane are separated by a substrate; the radiating patch have two pairs
of orthogonal slits cut from the edge, this antenna has wide bandwidth in the frequency band of
(WLAN) and with a return loss ≤ −10 dB from 2.4 GHz to 2.48 GHz and from 5.12 GHz to 5.32
GHz exhibits circularly polarized far field radiation pattern. The proposed antennas have been
simulated and analyzed using method of moments (MoM) based software package Microwave
Office 2009 v9.0. The results show that the antenna has dual band frequency operation by using slit
load.
International Journal of Engineering Research and DevelopmentIJERD Editor
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Automation and Mechatronics Engineering,
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Reconfigurable Microstrip Patch Antenna for Frequency Diversity Using RF MEMSIOSR Journals
A novel reconfigurable patch antenna for frequency diversity is proposed by reconfiguring its
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Reconfigurable Microstrip Patch Antenna for Frequency Diversity Using RF MEMSIOSR Journals
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1. PIFA Passive Array Based Low
Profile Spatial-Pattern Diversity
Antenna for Mobile Terminals
(Technical Report)
I. INTRODUCTION or Abstract
In this work we report a very compact, low cost, spatial-pattern diversity antenna system for
2.45GHz ISM band. The overall size of the diversity antenna (including ground) is
95×49×6.4mm3, which is suitable for use in mobile terminals like mobile phone, laptop, etc. The
geometry of the proposed antenna is depicted in Figs. 1 and 2 and the dimensions are listed in
Table I. The proposed diversity antenna system consists of two sets of passive arrays, A1 and A2
each of which consists of a probe fed planar inverted ‘F’ antenna (PIFA) and an open circuited
PIFA. Since the open circuited PIFA does not have the feeding probe, henceforth it would be
referred as planar inverted ‘L’ antenna or PILA. The PIFA and PILA radiators are placed anti-symmetrically
on a small slitted ground of size 47×24mm2. The anti-symmetric placement
consists of short-end of PILA placed close to the radiating end of PIFA, and introduces strong
mutual coupling between them. The PIFA and PILA antennas are separated by a longitudinal slit
which contributes to PILA work as a director. The directive nature of the passive array increases
as we reduce the size of PILA.
In this work, first we design a directive passive array. Next we arrange two such passive
arrays in such a way that they radiate in complementary regions of space. Besides, we take
necessary measures to keep mutual coupling between driven PIFAs as low as possible. The
proposed antenna solution has been realized using copper sheet of 0.397mm thickness. 50Ω
RG405 coaxial cables (d = 0.51mm, D = 1.7mm and r e = 2.1) have been used to feed the PIFAs.
Give important results about bandwidth, back-lobe radiation, S12, pattern correlation factor, etc?
2. H
H
Fig. 1 The proposed pattern (spatial) diversity antenna
A2
A1
H
H
WP
LG
WP
LG
WP
LPP
Gap-Y
Fig. 2 Top view of the proposed pattern (spatial) diversity antenna. Separation distance between PIFA and PILA?
A2
A1
W LAP G
LPP
ΔLFeed WSlot
WSlot WG
LAP
WP
ΔLGap-X Feed
3. TABLE-I
List of Structural Parameters of the Pattern Diversity Antenna
Copper sheet thickness: 0.397mm, Wp = 5mm, H = 6mm
Ground plane
LG 47 mm
W 24 mm
WSlot 4 mm
Gap-X 1 mm
Gap-Y 1 mm
PIFA LAP 24 mm
ΔLFeed 3 mm
PILA LPP 18 mm
Transverse
distance
between PIFA and
PILA
II. PRINCIPLES OF OPERATION OF THE PROPOSED PASSIVE ARRAY
In order to understand the principles of operation of the proposed antenna, first we study the
behavior of the PIFA alone on a continuous ground, 50×24mm2. The antenna structure is shown
in Fig. 3 and all its dimensions are summarized in Table II. |S11| of this antenna is plotted in Fig.
4, which shows that the antenna resonates at about 2.504 GHz. It may be pointed out that the
antenna resonant frequency is sensitive to the size of the ground plane and any slit cut into it.
Fig. 3: PIFA on a continuous ground (50mm×24mm) define the various parameters
4. TABLE-II
List of Design Parameters of the PIFA Shown in Fig. 3
Copper sheet thickness: 0.397mm
LG
W
LAP
WP
H
ΔLFeed
50 mm
24 mm
25 mm
5 mm
6 mm
3 mm
Fig. 4 |S11| of a PIFA on continuous ground plane
Next we place an identical sized PILA very close to the PIFA as shown in Fig. 5. The
transverse separation between the antennas is ? The open ends of PIFA and PILA are arranged on
the opposite sides. The geometry is similar to that of a dipole which has been cut into two
identical halves and arranged as shown. The asymmetric placement produces strong mutual
coupling between the monopoles [1]. Due to the coupling, the original mode of resonance of the
PIFA gets split into two coupled modes of operation at f0_Low = 2.08 GHz and f0_High = 2.77 GHz,
Fig. 6. The inductive mutual coupling through the current on the common ground between the
resonators might be responsible for this phenomenon.
5. Fig. 5 Driven and passive PIFA placed asymmetrically on continuous ground (50mm×24mm)
Define the separation between PIFA and PILA
TABLE-III
List of Design Parameters of the Structure Shown in Fig. 5
Copper sheet thickness: 0.397mm, Wp = 5mm, H = 6mm
Ground Plane LG 47 mm
W 24 mm
PIFA LAP 25 mm
ΔLFeed 3 mm
PILA LPP LAP
Transverse
separation
between
PIFA
and PILA?
6. Fig. 6 |S11| of PIFA and an identical PILA on continuous ground plane (as shown in Fig. 5)
Figs 6 and 3 may be combined.
E In Yagi-
Uda type antennas, the sizes of the passive elements are made larger or smaller than
the active driven element so that the passive elements work as reflector or director, respectively.
Electrically, the director current leads and the reflector current lags the current of the driven
element [2], [3]. However, it is found for the passive array shown in Fig. 5 that the change in the
length of PILA does not make the passive element work as director or reflector. Instead, the
change in the length of PILA gives rise to change in the resonant frequencies of coupled modes.
Fig. 7 shows |S11| plot for different values of ΔL, where ΔL = (LAP – LPP). These studies imply
that the longer PILA adds more capacitance to the coupled system and the coupled mode resonant
frequencies shift to lower values. The radiation patterns for this array show an interesting
behavior. The pattern in the xz-plane ( f = 0 ° ) is plotted in Fig. 8 for different values of LPP
at the lower resonant frequency, and is found to be monopole-like. The size of PILA influences
the back-lobe radiation and directivity. The higher directivity is achieved at the cost of larger
u
back-lobe radiation. The radiation pattern E(f = 0°)
at the higher resonant frequency is dipole-like
with maxima at q =±90°and near null at q =0°, Fig. 9.
7. Fig. 7 |S11| of the passive array shown in Fig. 5 for different values of ΔL. (—) line is for ΔL = 6mm, (—) line is for ΔL
= 3mm, (—) line is for ΔL = 0mm, (—) line is for ΔL = – 3mm, (—) line is for ΔL = – 6mm.
8. ur
Fig. 8 E(f = 0°)
(in dB) of the passive array shown in Fig. 5 for different values of ΔL. (—) line is for ΔL = 6mm,
(—) line is for ΔL = 3mm, (—) line is for ΔL = 0mm, (—) line is for ΔL = – 3mm, (—) line is for ΔL = – 6mm. For all
values of ΔL, the pattern is simulated at the corresponding lower resonant frequency.
ur
Fig. 9 E(f = 0°)
(in dB) of the structure shown in Fig. 5 for different values of ΔL. (—) line is for ΔL = 6mm, (—)
line is for ΔL = 3mm, (—) line is for ΔL = 0mm, (—) line is for ΔL = – 3mm, (—) line is for ΔL = – 6mm. For all
ur
values of ΔL, E(f = 0°)
is simulated at their corresponding upper resonant frequency.
For the PILA to work as a director element we cut a narrow slit in between the PIFA and
PILA [see Fig. 10 and Table IV]. This slit serves two purposes. First, it splits the ground plane
between driven and passive antennas. As a result, the coupling between the antennas gets
modified and the antenna with slitted ground and identical sized PIFA and PILA resonates at
three frequencies, 2.2 GHz, 2.5 GHz, and 3.1 GHz[Fig. 11]. The resonance at 2.5 GHz
corresponds to that of the uncoupled mode, and the coupled mode resonances have moved to
higher frequencies due to the capacitive effect of slit.
The other effect of the coupling slit is to introduce capacitance in the current path between
driven and passive antennas. Generally, director elements are loaded capacitively by using
lumped capacitors or tunable varactor diodes to make the director current lead the current of the
driven element [4]. In the proposed structure, this capacitance is introduced by the slit. The slit is
easier to fabricate along with rest of the antenna and is a low cost solution. The slit capacitance
ur
may be determined by modeling the slit as a slot line. Figure 12 depicts the normalized E(f = 0°)
pattern at 2.5 GHz? In this array, the power radiated in -x direction (towards PILA) is 2.96dB
higher than the power radiated in +x direction. Since the radiation gets enhanced towards PILA, it
therefore acts as a director. We, next study the effect of variation of slit width on the directivity of
radiation pattern.
9. Fig. 10 Active and passive PIFA placed asymmetrically on slitted ground (Ground size is 50mm×24mm and slit width
is 0.5mm). Transverse separation between PIFA and PILA?
TABLE-IV
List of Design Parameters of the antenna Structure Shown in Fig. 10
Copper sheet thickness: 0.397mm, Wp = 5mm, H = 6mm
Ground Plane
LG 47 mm
W 24 mm
WSlot 0.5 mm
PIFA LAP 25 mm
ΔLFeed 3 mm
PILA LPP LAP
Transverse
separation
10. Fig. 11 |S11| of the structure shown in Fig. 10
ur
Fig. 12 Normalized E(f = 0°)
pattern (in dB) at 2.5GHz or 3.1GHz?
A. Variation of Array Performance with Change in Wslot
In the proposed passive array, the slit width Wslot is an important design parameter. The slit
width influences both the directivity and the resonant frequencies of the antenna. The variation of
11. |S11| for various values of Wslot is plotted in Fig. 13. It shows that the resonant frequency for the
uncoupled mode decreases with increase in slit width. The resonant frequencies for the coupled
modes however remain mostly unchanged. The uncoupled mode behavior may be explained by a
simple equivalent circuit model for the antenna presented in Fig. 14. Here, PIFA is modeled as a
parallel resonating network where R represents radiation resistance and conductor losses in PIFA.
LPatch is the inductance and C is the capacitance associated with PIFA, LG_Active is the inductance of
the ground underneath PIFA, LG_Passive is the inductance of the rest of the ground associated with
the ground underneath PILA, and CSlot is the slit capacitance. The effective inductance Leffective for
this mode is therefore given by
Leffective = LPatch + [(LG_Active – ω2LG_ActiveLG_PassiveCSlot)/( 1 – ω2(LG_Active + LG_Passive)CSlot)]. ...(1)
This expression indicates that for the continuous ground case (i.e. for Wslot = 0, CSlot = ¥),
Leffective = LPatch + (LG_Active║LG_Passive), which is the minimum value of Leffective. Equation (1) also
indicates that Leffective increases with increase in Wslot or decrease in CSlot. Increase in Leffective brings
down the resonant frequency. Therefore (1) predicts that resonant frequency decreases with
increase in slit width Wslot. This prediction agrees with the results presented in Fig. 13 for the
uncoupled mode. The tuning of uncoupled mode resonant frequency may also be realized by
attaching a biased varactor diode across the slit. The effect of slit width on radiation pattern is
studied next.
CSlot is the capacitance in the current path between the driven and passive element. The
capacitive reactance of CSlot increase with increase in slot width Wslot influences the directivity of
the radiation pattern, Fig. 15. As we increase Wslot from zero value, the directivity increases
initially. For Wslot larger than 4 mm, directivity starts decreasing. This is expected because
increasing Wslot beyond a certain limit weakens coupling between PIFA and PILA. The size
constraint of the antenna also dictates small slit width. The figure of merit for the directive
passive array is the back-lobe radiation. The smallest value of back-lobe radiation is
-8dB corresponding to Wslot =?
12. Fig. 13 |S11| of the structure shown in Fig. 10 for different values of WSlot. (—) line is for WSlot = 0 mm, (—) line is for
WSlot = 2 mm, (—) line is for WSlot = 4 mm, (—) line is for WSlot = 6 mm.
CSlot
R
LPatch
LG_Active LG_Passive
C
Fig. 14 Simplistic Lumped Circuit Model of the structure shown in Fig. 10. The encircled portion of the circuit
represents equivalent circuit of the slitted ground.
Equivalent circuit of
the slitted ground
13. ur
Fig. 15 E(f = 0°)
(in dB) of the structure shown in Fig. 10 for different values of WSlot. (—) line is for WSlot = 0 mm,
ur
(—) line is for WSlot = 2 mm, (—) line is for WSlot = 4 mm, (—) line is for WSlot = 6 mm. E(f = 0°)
is simulated at
resonant frequency of each structure.
B. Variation of Array Performance with Change in Length ΔL of PILA
The resonant frequency and radiation pattern of the proposed passive array can also be
controlled by tuning the length of PILA. It is found that the uncoupled mode resonant frequency
is not affected by the change in length ΔL of PILA. However, the radiation pattern at this
frequency becomes more directive as we decrease ΔL i.e. as we decrease ΔL, the PILA works as
a better director. This is shown in Fig. 17. In addition, there is a beam squint of about +15°.
This is due to the fact that PIFA and PILA act as travelling wave array and the phase difference
between them produces the squint. The minimum value of back-lobe is found to be ?dB
corresponding to ΔL=? Determine the optimum values of Wslot and ΔL for maximum suppression
of back-lobe and use it in the next section.
C. Variation of Array Performance with Change in Position of Slit??
One may carry out parametric studies on the effect of slit position on array performance. Can the
equivalent circuit model of Fig. 14 explain the effect of slit position on the resonant frequency of
uncoupled mode?
14. Fig. 16 |S11| of the structure shown in Fig. 10 for different values of WSlot. (—) line is for WSlot = 0 mm, (—) line is for
WSlot = 2 mm, (—) line is for WSlot = 4 mm, (—) line is for WSlot = 6 mm. Should plot variation with ΔL?
ur
Fig. 17 E(f = 0°)
(in dB) of the structure shown in Fig. 10 for different values of WSlot. (—) line is for WSlot = 0 mm,
ur
(—) line is for WSlot = 2 mm, (—) line is for WSlot = 4 mm, (—) line is for WSlot = 6 mm. E(f = 0°)
is simulated at
15. resonant frequency of the structure at 2.5GHz?. Why there is a plot for WSlot = 0 mm? Should show variation with
ΔL?
III. DESIGN OF THE PROPOSED PASSIVE ARRAY
In the last section we have shown that the resonant frequency decreases with increase in Wslot.
In presence of the PILA (with ΔL = 0), the resonant frequency of the driven PIFA (on slitted
ground with 0.5 mm slit width) was 2.49 GHz [Fig. 11]. But for 6mm slit width, resonant
frequency decreased to 2.38 GHz [Fig. 13]. Hence, after designing the antenna for desired
radiation pattern, one needs to readjust the dimensions LG and LAP to make the antenna radiate in
the desired band of frequency. In spite of this design complexity, the proposed structure has the
advantage that widening of slit makes the antenna more compact.
In this work, after setting Wslot = 4 mm and ΔL = -6 mm, we have adjusted LG and LAP to make
the passive array radiate at 2.45GHz ISM band. In the final design LG = 47 mm, WG = 24 mm [see
Fig. 18 and Table V]. Figure 19 shows that the antenna operates in 2.45 GHz ISM band and its
return loss bandwidth is 100MHz, which is more than the bandwidth of 2.45 GHz WLAN. What
about other resonances? Figure 20 shows Eur
pattern in xz plane and Fig. 21 shows Eur
pattern in
xy plane. In this antenna, the power radiated in -x direction is 7.61dB higher than the power
radiated in +x direction [Fig. 20].
Fig. 18 Final design of the passive array
16. TABLE-V
List of Design Parameters of the Structure Shown in Fig. 18
Copper sheet thickness: 0.397mm, Wp = 5mm, H = 6mm
Ground Plane
LG 47 mm
W 24 mm
WSlot 4 mm
PIFA LAP 25 mm
ΔLFeed 3 mm
PILA LPP 19 mm
Fig. 19 |S11| of designed passive array shown in Fig. 18. What about the other two modes?
17. Fig. 20 Normalized Eur
pattern (in dB) of passive array (shown in Fig. 18) in xz plane
Fig. 21 Normalized Eur
pattern (in dB) of passive array (shown in Fig. 18) in yz plane
IV. DESIGN OF THE PROPOSED SPATIAL-PATTERN DIVERSITY ANTENNA
Next we arrange two identical passive PIFA arrays (A1 and A2) in such a way that they radiate
in complementary regions of space and their mutual coupling becomes small. For this, the arrays
18. are placed in diagonally opposite quadrants. Figs 1 and 2 show the proposed arrangement.
Dimensions of the array are summarized in Table I. The array A2 is the translated and shifted
version of array A1. In this arrangement A2 is positioned with respect to A1 such that it is not
illuminated by the radiation of A1, and vice versa. This is achieved by placing the arrays in
diagonally opposite quadrants and positioning the open ends of A1 and A2 away from each other
as shown. The passive arrays are separated by a distance of 1 mm along x- and y-axis. Due to
this arrangement we achieve high isolation between two arrays (|S12| < -18 dB over the -10 dB
return loss bandwidth) [Fig. 23]. The figure should include other resonances also? Result shows
that the proposed antenna operates in 2.45 GHz ISM band [Fig. 22]. Bandwidth of WLAN (in
2.45 GHz band) is 80 MHz. In this work we got 100 MHz band width. Figure 24 to Fig. 27 shows
normalized radiation Eur
pattern in xz and yz planes for A1 driven (A2 terminated in matched
load), and A2 driven (A1 terminated in matched load). Results show that power radiated by A1 in
+x direction is –7.52dB lower than the power radiated in –x direction and power radiated by A2 in
-x direction is –8.4dB lower than the power radiated in +x direction. Hence, the proposed antenna
has very low antenna pattern correlation, how much?
The major contributions of this work are as follows:
(a) The PIFA antenna may be tuned electrically by cutting a slit in the ground plane in the
longitudinal direction. The amount of capacitive reactance of the slit can be varied by
mounting a reverse-biased varactor diode across it. Further studies on this aspect may
produce a publication if not already reported.
(b) Although PIFA is a monopole antenna, a dipole like radiation pattern in its f =0° plane
may be obtained by placing an identical sized PILA in its close proximity, Fig. 5 and 9.
(c) A passive array of PIFA and PILA on a slitted ground may be employed as an end-fire
antenna, the directivity and back-lobe radiation of which can be controlled by means of
slit width or fixed slit plus a varactor diode across it, Fig.15.
(d) A passive array of PIFA and PILA on a slitted ground may be employed as an end-fire
array which can be scanned electronically, Fig. 17. This may be further investigated by
increasing the number of elements and slits.
(e) Spatial pattern diversity antenna may be realized by employing a pair of passive arrays of
PIFA and PILA on a slitted ground, Figs. 1,2, 24 and 25.
19. Fig. 23 |S11| and |S12| (in dB) of the proposed spatial-pattern diversity antenna. Other resonances?
Fig. 24 Normalized Eur
pattern (in dB) of the proposed spatial-pattern diversity antenna (A1 driven and A2 terminated
in matched load) in xz plane
( ) |S11|
( ) |S12|
20. Fig. 25 Normalized Eur
pattern (in dB) of the proposed spatial-pattern diversity antenna (A2 driven and A1 terminated
in matched load) in xz plane
Fig. 26 Normalized Eur
pattern (in dB) of the proposed spatial-pattern diversity antenna (A1 driven and A2 terminated
in matched load) in yz plane
21. Fig. 27 Normalized Eur
pattern (in dB) of the proposed spatial-pattern diversity antenna (A2 driven and A1 terminated
in matched load) in yz plane
REFERENCES
1. K. L. Virga and Y. Rahmat-Samii, “Low-profile enhanced-bandwidth PIFA antennas for
wireless communications packaging,” IEEE Transaction on Antennas And Wireless
Propagation Letters, vol. 45, No. 10, pp. 1879–1888, Oct. 1997
2. J. D. Kraus, “Antennas”
3. C. A. Balanis, “Antenna Theory Analysis and Design”
4. Y. Yusuf and X. Gong, “A low-cost patch antenna phased array with analog beam
steering using mutual coupling and reactive loading,” IEEE Antennas And Wireless
Propagation Letters, vol. 7, pp. 81–84, 2008.