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40120140504010 2

  1. 1. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 72 A NOVEL COMPACT SINGLE FED POLARIZATION RECONFIGURABLE ANTENNA FOR WIRELESS LAN SYSTEMS Neethu P S1 , Sudha T2 1 (Student, Department of Electronics and Communication, NSS College of Engineering, Palakkad) 2 (Professor, Department of Electronics and Communication, NSS College of Engineering, Palakkad) ABSTRACT A single-feed square microstrip patch antenna with polarization reconfigurability is presented in this paper. Antenna is designed for the WLAN frequency, 2.4GHz (2.4-2.484GHz). A diagonal slot is inserted in the square patch and a PIN diode is placed on the slot. By switching PIN diode on the slot, polarization reconfigurability is achieved. When the diode is in the “off-state” antenna radiates with circular polarization, and in the “on-state” antenna radiates with linear polarization. The square patch antenna was excited by microstrip line feed and quarter wave transformer is used for impedance matching. Keywords: CP, LP, Microstrip Antenna, PIN Diode, Reconfgurable. 1. INTRODUCTION Microstrip antennas are widely used due to their low profile, light weight, and easy fabrication [1]. Reconfigurable antennas provide multiple functionality within a limited volume space. Reconfigurable antenna with polarization diversity can realize frequency reuse, which expands the capability of communication systems, and are useful when the operating frequency band is limited. Polarization diversity antennas can also alleviate the harmful influence caused by multipath effects [2]. Microstrip antennas in their basic form normally provide linear polarization; circular polarization (CP) operation may be obtained by certain modifications to the basic antenna geometry and/or feed. Circular polarization (CP) is more attractive in the applications of wireless communications since the antennas of the transmitter and receiver do not need to be aligned [3]. Circular polarization can be obtained if two orthogonal modes are excited with a 900 time-phase difference between them [4]. Reconfigurable antenna in [5] uses dual feed to produce circular polarization. Compared to dual-fed structure single-fed structure is simple and smaller in size. A single feed structure in [7] switches between two circular and linear polarization, at expense of five INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET) ISSN 0976 – 6464(Print) ISSN 0976 – 6472(Online) Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME: www.iaeme.com/ijecet.asp Journal Impact Factor (2014): 7.2836 (Calculated by GISI) www.jifactor.com IJECET © I A E M E
  2. 2. International Journal of Electronics and Communication Engineering & 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. switches and three matching stubs. Simple antenna structure with lower size and cost are preferred for wireless applications. In this paper, a microstrip patch antenna with switchable polarization using single diode is presented. A diagonal slot in the square patch produces circular polarization, and inserting diode in the slot produces a short circuit across the slot resulting in LP. Hence the diode can be biased on and off to switch polarization and makes the antenna suitable for reconfigurable antenna was designed and simulated using HFSS v15 on FR4 epoxy substrate of dielectric constant 4.4 and height of substrat and its design parameters are discussed. Simulated results, such as radiation pattern, gain plot, return loss curve etc. are discussed in section 3 2. ANTENNA DESIGN Structure of square patch antenna is shown in figure 1. Antenna structure consists of square patch of dimension 28.541mm on a substrate. The substrate is made of 1.6mm thick FR4 epoxy resin of relative permittivity 4.4. The ground plane covers the rectangular shaped substrate with a side of 66.7x 80mm. Ground plane is a full ground plane with dimensions same as bottom face of A rectangular slot is cut out diagonally from centre of square patch. Slot dimensions are taken according to the equation 2.1, where `W Slot length PIN diodes are used as switches to achieve polarization reconfigurability. A PIN diode is placed on the slot. The diode in the ``on-state,'' was simulated by using metal tape ( model used is MA4P2741141T [6], slot is assigned properties of this model. Fig1: Configuration of square patch antenna International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 73 switches and three matching stubs. Simple antenna structure with lower size and cost are preferred In this paper, a microstrip patch antenna with switchable polarization using single diode is diagonal slot in the square patch produces circular polarization, and inserting diode in the slot produces a short circuit across the slot resulting in LP. Hence the diode can be biased on and off to switch polarization and makes the antenna suitable for wireless applications. The reconfigurable antenna was designed and simulated using HFSS v15 on FR4 epoxy substrate of dielectric constant 4.4 and height of substrate equal to 1.6 mm. In section 2, structure of the antenna ussed. Simulated results, such as radiation pattern, gain plot, return ion 3. Structure of square patch antenna is shown in figure 1. Antenna structure consists of square a substrate. The substrate is made of 1.6mm thick FR4 epoxy resin of relative permittivity 4.4. The ground plane covers the rectangular shaped substrate with a side of 66.7x 80mm. Ground plane is a full ground plane with dimensions same as bottom face of A rectangular slot is cut out diagonally from centre of square patch. Slot dimensions are taken according to the equation 2.1, where `W' is the length of square patch. length =W=2:72 (1) Slot width =W=27:2 PIN diodes are used as switches to achieve polarization reconfigurability. A PIN diode is placed state,'' was simulated by using metal tape (10×1mm slot is assigned properties of this model. Configuration of square patch antenna Technology (IJECET), ISSN 0976 – © IAEME switches and three matching stubs. Simple antenna structure with lower size and cost are preferred In this paper, a microstrip patch antenna with switchable polarization using single diode is diagonal slot in the square patch produces circular polarization, and inserting diode in the slot produces a short circuit across the slot resulting in LP. Hence the diode can be biased on and wireless applications. The reconfigurable antenna was designed and simulated using HFSS v15 on FR4 epoxy substrate of , structure of the antenna ussed. Simulated results, such as radiation pattern, gain plot, return Structure of square patch antenna is shown in figure 1. Antenna structure consists of square a substrate. The substrate is made of 1.6mm thick FR4 epoxy resin of relative permittivity 4.4. The ground plane covers the rectangular shaped substrate with a side of 66.7x 80mm. Ground plane is a full ground plane with dimensions same as bottom face of substrate. A rectangular slot is cut out diagonally from centre of square patch. Slot dimensions are taken PIN diodes are used as switches to achieve polarization reconfigurability. A PIN diode is placed 10×1mm2 ). PIN diode
  3. 3. International Journal of Electronics and Communication Engineering & 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. In this simulation, uses 3 for the ON state and perfect open circuit for the OFF state of the PIN diode. Antenna is fed by microstrip line and a quarter wave transformer at 2.4GHz. Actual input impedance 243 of antenna is matched to 50 quarter wave transformer. Details of the design paramete Details of the design parameters PATCH SLOT QUARTERWAVE TRANSFORMER MICROSTRIP FEED LINE Basically, in this paper, the square microstrip patch with quarter wave transformer fed is simulated using computer simulation, HFSSv15 which is a full wave analysis tool based on the finite element method (FEM). Antenna operating frequency is 2.4GHz, at t lowest return loss. When the diode is in the ON state the applied field can pass through the switch and can follow a straight path hence the polarization is linear. Diode in the OFF state introduces variation in the regular geometry of the antenna straight and the path of the field is changed such that the resulting polarization is RHCP. The antenna structure that switches between LHCP and LP can be designed, if the orientatio changed as shown in Figure 2. Fig2: Circular polarization for square patch with slots on patch Fig3: Different senses of the proposed antenna International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 74 for the ON state and perfect open circuit for the OFF state of the PIN diode. Antenna is fed by microstrip line and a quarter wave transformer at 2.4GHz. Actual input of antenna is matched to 50 microstrip feed line at resonant frequency b quarter wave transformer. Details of the design parameters are summarized in table. Details of the design parameters LENGTH(mm) BREADTH(mm) 28.541 28.541 10 1 QUARTERWAVE TRANSFORMER 19.971 0.723 MICROSTRIP FEED LINE 28.541 3.059 Basically, in this paper, the square microstrip patch with quarter wave transformer fed is simulated using computer simulation, HFSSv15 which is a full wave analysis tool based on the finite element method (FEM). Antenna operating frequency is 2.4GHz, at this frequency antenna shows lowest return loss. When the diode is in the ON state the applied field can pass through the switch and can follow a straight path hence the polarization is linear. Diode in the OFF state introduces etry of the antenna, there is no such path available for the fields to go straight and the path of the field is changed such that the resulting polarization is RHCP. The antenna structure that switches between LHCP and LP can be designed, if the orientatio Circular polarization for square patch with slots on patch Different senses of the proposed antenna Technology (IJECET), ISSN 0976 – © IAEME for the ON state and perfect open circuit for the OFF state of the PIN diode. Antenna is fed by microstrip line and a quarter wave transformer at 2.4GHz. Actual input microstrip feed line at resonant frequency by using BREADTH(mm) Basically, in this paper, the square microstrip patch with quarter wave transformer fed is simulated using computer simulation, HFSSv15 which is a full wave analysis tool based on the finite his frequency antenna shows lowest return loss. When the diode is in the ON state the applied field can pass through the switch and can follow a straight path hence the polarization is linear. Diode in the OFF state introduces there is no such path available for the fields to go straight and the path of the field is changed such that the resulting polarization is RHCP. The antenna structure that switches between LHCP and LP can be designed, if the orientation of the slot is
  4. 4. International Journal of Electronics and Communication Engineering & 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. 3. RESULTS AND INFERENCES The switching conditions considered to achieve desired polarization reconfigurabilty are given in Table 2. Case1 is taken as antenna without diode, which resonates at 2.412GHz with return loss of -21dB. In case1 antenna shows a band width of 48MHz which is antenna with diode in the ON state shows 54MHz BW which is 0.2% greater than the previous one and both are suitable for wireless LAN applications. Circularly polarized antenna shows an axial ratio of 1.04 at 2.41GHz, and the ax resonates at 2.44GHz , shift of frequency occurs due to insertion of the diode. exhibit good impedance matching at resonant frequency. Also produces a good broadside radiation pattern with RHCP and LP characteristics. 2D radiation pattern is shown in Fig gain patterns in the X-Z (E) plane and Y band of operation. E and H plane patterns are almost similar patterns for antenna with LHCP are also plotted in Fig: 12. Antenna with LHCP shows similar results as that of RHCP. Antenna performance parameters for each switching condition of polarization DIODE POLARIZATION CASE1 OFF RHCP CASE2 ON LP Fig 4: Simulated return loss of antenna for case Fig 5: Simulated return loss of antenna for case2 International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 75 FERENCES The switching conditions considered to achieve desired polarization reconfigurabilty are given in Table 2. Case1 is taken as antenna without diode, which resonates at 2.412GHz with return 21dB. In case1 antenna shows a band width of 48MHz which is 2% of the centre frequency, antenna with diode in the ON state shows 54MHz BW which is 0.2% greater than the previous one and both are suitable for wireless LAN applications. Circularly polarized antenna shows an axial ratio of 1.04 at 2.41GHz, and the axial ratio BW (<3dB) is 18 MHZ. Antenna in second case resonates at 2.44GHz , shift of frequency occurs due to insertion of the diode. Antenna in both cases exhibit good impedance matching at resonant frequency. Also produces a good broadside radiation rn with RHCP and LP characteristics. 2D radiation pattern is shown in Fig: 11 plane and Y-Z (H) plane are plotted for lowest axial ratio in frequency band of operation. E and H plane patterns are almost similar for both cases. The simulated gain patterns for antenna with LHCP are also plotted in Fig: 12. Antenna with LHCP shows similar Antenna performance parameters for each switching condition of polarization POLARIZATION BW[MHz] BW[PERCENTAGE] RHCP 48 2 LP 54 2.2 Simulated return loss of antenna for case Simulated return loss of antenna for case2 Technology (IJECET), ISSN 0976 – © IAEME The switching conditions considered to achieve desired polarization reconfigurabilty are given in Table 2. Case1 is taken as antenna without diode, which resonates at 2.412GHz with return 2% of the centre frequency, antenna with diode in the ON state shows 54MHz BW which is 0.2% greater than the previous one and both are suitable for wireless LAN applications. Circularly polarized antenna shows an axial is 18 MHZ. Antenna in second case Antenna in both cases exhibit good impedance matching at resonant frequency. Also produces a good broadside radiation : 11. The simulated plane are plotted for lowest axial ratio in frequency or both cases. The simulated gain patterns for antenna with LHCP are also plotted in Fig: 12. Antenna with LHCP shows similar Antenna performance parameters for each switching condition of polarization GAIN[dB] 1.7 1.6
  5. 5. International Journal of Electronics and Communication Engineering & 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. Fig 6: Radiation Fig 7: Radiation International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 76 Radiation pattern of antenna for case 1 Radiation pattern of antenna for case 2 Technology (IJECET), ISSN 0976 – © IAEME
  6. 6. International Journal of Electronics and Communication Engineering & 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. Fig 8: Fig 9: Fig 10: International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 77 Fig 8: Gain of antenna for case1 Fig 9: Gain of antenna for case 2 Fig 10: Axial ratio of antenna with RHCP Technology (IJECET), ISSN 0976 – © IAEME
  7. 7. International Journal of Electronics and Communication Engineering & 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. Fig 11: Radiation pattern of antenna with LHCP International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 78 Radiation pattern of antenna with LHCP Fig 12: 2D radiation patte Technology (IJECET), ISSN 0976 – © IAEME
  8. 8. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online), Volume 5, Issue 4, April (2014), pp. 72-79 © IAEME 79 4. CONCLUSION Microstrip patch antenna with switchable polarization is presented. Polarization can be switched between RHCP, LHCP and LP, by controlling the state of one PIN diode. Basic idea of the proposed design is, slot on the patch, and redirect the surface current, producing circular polarization. Inserting diode in slot short circuits the slot and produce LP. Electronic reconfiguration is achieved using PIN diode. Antenna shows good impedance matching for both polarization senses and broadside radiation pattern with moderate gain. Proposed antenna is a simple and compact design with single feed suitable for wireless LAN applications. Antenna with reconfigurability in three senses of polarization is left for future study. REFERENCES [1] Youngje Sung, Investigation into the Polarization of Asymmetrical- Feed Triangular Microstrip Antennas and its Application to Reconfigurable Antennas IEEE Transactions on Antennas and Propagation, Vol. 58, NO. 4, April 2010. [2] Xue-Xia Yang, Bing-Cheng Shao, Fan Yang, Atef Z. Elsherbeni and Bo Gong, A Polarization Reconfigurable Patch Antenna With Loop Slots on the Ground Plane, IEEE Antennas and Wireless Propagation Letters,Vol. 11,2012. [3] Shih-Hsun Hsu, Kai Chang [2007]: A Novel Reconfigurable Microstrip Antenna with Switchable Circular Polarization [J]’, IEEE Antennas and Wireless Propagation Letters, Vol. 6, 2007: 160162. [4] Balanis, C.A, Antenna Theory: Analysis and Design (Hoboken, New Jersey, John Wiley and Sons, 1997). [5] Xue-Xia Yang1, Bo Gong1, Fang Yang Atef Z. Elsherbeni, A reconfigurable patch antenna with quadri-polarization states using dual feed ports, Antennas and Propagation Society International Symposium(APSURI),2012 IEEE. [6] Data Sheet MA4P274-1141T PIN Diodes, MA-com, Application Note. [7] G Boyon Kim, Bo pan, Symeon Nikolaou, Young-Sik Kim, John Papapolymerou, and Manos M. Tentzeris, A Novel Single-Feed Circular Microstrip Antenna With Reconfigurable Polarization Capability, IEEE Trans.on Antennas and Propagation, VOL. 56, 2008. [8] Uma Shankar Modani and Anubhav Kanwaria, “Triangular Slot Circular Patch Antenna for Circular Polarization Reconfigurability”, International Journal of Electronics and Communication Engineering & Technology (IJECET), Volume 4, Issue 4, 2013, pp. 188 - 197, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472. [9] Ros Marie C Cleetus and T.Sudha, “Design and Analysis of a Frequency and Pattern Reconfigurable Microstrip Patch Antenna using Various Electronic Switching Components”, International Journal of Electronics and Communication Engineering & Technology (IJECET), Volume 4, Issue 4, 2013, pp. 262 - 271, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472. [10] Uma Shankar Modani and Anubhav Kanwaria, “Triangular Slot Circular Patch Antenna for Polarization Reconfigurability”, International Journal of Electronics and Communication Engineering & Technology (IJECET), Volume 4, Issue 4, 2013, pp. 166 - 175, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.

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