This presentation contains very basic knowledge of Antenna in Telecom sector for Engineering Students.

2. Q: What does Maxwell’s Equations tell?
A: Theygive the basic relation between electric field(E), magnetic field (H) and the source.
Q: Why Radiation patterns are plotted on dB scales?
A: Because when linear scale is adopted the power radiation pattern and electric field
radiation pattern look much different. But when dB scale is adopted then they look similar
as
10log(P/Pmax)=20log(E/Emax)
Q: What is NOISE?
A: Noise is any unwanted signal that could change or effect the current state (i.e 01 or
10)
Q: What is convolution?
A: Converting the signal into basic signal that is impulse is called convolution. Convolution
is done for the transmission of signal.
Q: What is interference?
A: Any interaction that disturbs speed, processing of system is interference. E.g Weather
effects signals, it is interference.
Q: Form circuit point of view, why “Antenna impedance” is an important parameter?
A: Antenna is a transition device, linking transmission lines to radio waves. Thus from
circuit point of view, antenna is just a load to transmission lines, therefore “antenna
impedance” is important parameter.

3. Q: What is Radiation Resistance?
A: It is the amount of resistance which will dissipate the same amount of power antenna radiates
when current is equal to input current at terminals.
Rr = 2Pt/Iin
2
Q:What is Loss Resistance?
A: It is resistance due to Conductor Loss and Dielectric Loss offered by lossy materials if used.
Q: What is condition of Antenna Impedance for a matched load?
A:If an antenna is directly connected to a source of impedance Zs, then for a matched load the
input impedance condition is,
Zs=Za
*=Ra-jXa
Q:What is Cross-Talk?
A: It is an after-effect of interference on voice channels. It is interference in the back ground due
to unwanted transmission.
Q: Why there happens blocking/missing of calls?
A: Calls are blocked or missed due to errors in digital signaling which arise due to interference on
control channels.
Q: For mobile phone antennas, determine the values of VSWR and Lrt?
A: For mobile phone antennas,
VSWR<3 ; Lrt > 6dB

4. Q: What is impedance matching?
A: Impedance matching is a process to remove mismatch loss. To minimizereflection co-
efficient, to reducethe power reflected from the load(antenna)and to maximizethe power
delivered to the antenna.
Impedanceof antennashould be reasonablyclose to amplifier impedance,otherwise the
signal will be reflected from the amplifier and will not be radiated by antenna.
Q: What is a protocol?
A: In networking, protocol is a setof rules that enables two devices to connectand
communicatewith each other. Protocols for computer networking all generallyusepacket
switching technique.
Q: What is “data sharing protocol” in NGN?
A: T.120 is data sharing protocol in NGN.
Q: What is transcoding?
A: Transcoding is process of converting a language , file or information from one coded
representation to another one.
Q: What does mean by Plane of Incidence?
A: Plane of Incidence means planecontaining the incident, reflectedand transmitted
waves.
Q: What is Free SpacePropagation Model?
A: Free Space Propagation Model is employed to determinereceived signal power when
there is un-obstructed LoS between Transmitterand Receiverantenna.

5. Q: Define Path Loss?
A: Path loss is difference (in dB) in effective transmitted and received power.
It may or may not include the antenna gains.
PL(dB)=10logPt/Pr
Q:Define Reflection, Diffraction, Scattering in terms of objects?
A: Reflection occurs when waves impinge on objects with dimension larger
than wavelength of wave.
Diffraction occurs when object has sharp edges.
Scattering occurs when radio path consists of large number of objects with
smaller dimension than wavelength of wave.
Q: Why the poles supporting line conductors are insulated?
A: Because current passing through line conductors shouldn’t be flown to
earth via these supports. To avoid the contact of current in lines with earth,
poles are kept insulated.
What is difference b/w micro-processor and micro-controller?
Microprocessors have only CPU inside them; they don’t have RAM, ROM and
other peripherals available on a chip. They have more OP-CODES and few
BIT-HANDLING INSTRUCTIONS. They find their apps., where relationship
b/w input and output isn’t defined. Such as creating documents, developing
soft wares, games, photo editing.

6. On the other hand, microcontrollers have CPU as well as RAM, ROM and other
peripherals of a chip. They have few OP-CODES and more BIT-HANDLIGNG
INSTRUCTIONS. They are used where relationship b/w input and output is
defined, e.g. watches, motor bikes, cars etc.
What is the principal of Antenna?
A radio transmitter provides electric current oscillating at radio frequency to
the terminals of antenna. It converts them into radio waves to travel across air,
earth and etcetera.
On receiving side, an antenna receives these radio waves and converts them
into electric signals, feed them into something like t.v, telephone and radio.
Q: State benefits of frequency re-use?
A: i)Capacity of system increases.
ii)Minimum interference.