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Right answer is (a) Wireless Body Area Network

To elaborate: A 2.4 GHz Wearable Microstrip ANTENNA is used for the Wireless Body Area Network. Detection of moving targets COMES under radar APPLICATION. Rectenna is a special rectifying antenna used to CONVERTS directly the MICROWAVE energy to the DC power. WiMax is an IEEE 802.16 standard used for communication.

Correct choice is (a) Spurious FEED radiation increases with increase in substrate thickness

For explanation: Microstrip line feed acts as an extent to PATCH and is connected to patch just LIKE a conducting strip. So the substrate thickness MAY increases leading to the increase in spurious radiation and this limits the bandwidth.

The correct CHOICE is (a) True

Explanation: Microstrip SLOT antenna uses a Babinet’s PRINCIPLE. It relates transmission/reception characteristics like radiation pattern, gain, and input impedance of those two complementary antennas. Slot antenna belongs to the aperture antenna and operates at 300MHZ to 30GHZ.

The correct choice is (a) Microstrip antenna

Explanation: In Microstrip antenna patch is CREATED on the DIELECTRIC SUBSTRATE using photo-etching. The shape and size of patch may vary the return loss.Horn, Wire and Lens doesn’t have any patch. Horn is a waveguide antenna and a wire antenna is MADE of dipoles.

Correct OPTION is (a) Microwave energy to DC power

Easy explanation: Rectenna is a SPECIAL rectifying antenna used to converts DIRECTLY the microwave energy to the DC power. This is used in the LONG distance links. It is a combination of antenna, rectification FILTERS and rectifiers.

The correct CHOICE is (a) 125Ω

The explanation: IMPEDANCE of N-element slot antenna \(Z_{in,N} = \frac{Z_{slot}}{N^2} \)

GIVEN N=2, Now \(Z_{in,N} = \frac{Z_{slot}}{N^2} = \frac{500}{4} = 125\Omega\)

Correct option is (c) Narrow Bandwidth

The best EXPLANATION: In coaxial feed, inner conductor is attached to PATCH and outer conductor to ground plane. Coaxial feeding fabrication is simple and has LOW SPURIOUS radiation which is its advantage. Due to asymmetries, higher modes are GENERATED and produces cross polarization radiation.

Right option is (C) Aperture coupling

Explanation: In Aperture coupling, TWO different substrates are separated by GROUND plane.This type of arrangement optimizes feed mechanism and radiating element.In Proximity coupling, the length of stub and length to width ratio of patch controls the match. Microstrip line feed acts as an extent to patch and is connected to patch just like a conducting strip. In coaxial feed, inner CONDUCTOR is attached to patch and OUTER conductor to ground plane.

The CORRECT option is (b) Tapered slot antenna

To EXPLAIN: MICROSTRIP slot antennas are usually poor end-fire radiators except tapered slot antenna. Slot antenna belongs to the aperture antenna and operates at 300MHZ to 30GHz.

The correct choice is (a) Slot ANTENNA

The explanation is: Slot antenna belongs to the aperture antenna and operates at 300MHZ to 30GHZ. It is obtained by removing a small area of metal from an infinite ground plane.

The correct answer is (d) FEM and FDTD

For explanation I would say: FEM (FINITE ELEMENT METHOD) and FDTF (finite difference time domain) techniques are used in the Microstrip antenna to solve the PARTIAL differential equations. MoM (Method of moments) is used to solve the mixed potential integrated equations obtained from the electromagnetic properties.

Right choice is (a) False

The best I can explain: Microstrip antenna is a printed antenna. It consists of a radiation patch on one side of dielectric and a ground plane on other side. The patch is connected to the feed line. In this at FABRICATION only, the feed line and MATCHING networks are FABRICATED SIMULTANEOUSLY.

The correct ANSWER is (c) Aperture COUPLING

To ELABORATE: In Aperture coupling, the ground plane separates two different SUBSTRATES. In Microstripline feed, the feed is connected to the patch like a CONDUCTING strip. The coaxial feed consists an inner conductor attached to the patch and ground plane to the outer conductor. The length of stub and length to width ratio of patch is used for matching in proximity coupling.

Right choice is (a) Babinet’s principle

The best I can explain: Babinet’s principle is used in slot antenna. It relates the fields obtained directly by slot antenna with CORRESPONDING complementary strip dipoles. It relates transmission/reception characteristics like radiation PATTERN, gain, and INPUT impedance of those TWO complementary antennas. Geo-optics is used in reflectors and Image THEORY in Corner reflectors.

Right option is (a) Center feed

The BEST EXPLANATION: A center feed slot has high radiation resistance and requires a matching network to match the antenna. Off-center, INCLINED slot and stub-tuning are some techniques USED to reduce the radiation resistance of slot antenna.

Right option is (a) True

The best I can EXPLAIN: FEM (Finite Element method) and FDTF (finite difference time domain) solve the partial DIFFERENTIAL EQUATIONS. HFSS is a commercial FEM solver for the electromagnetic structure of the ANTENNA. Those finite layers can be rectangles or TRIANGLES. FEM is used for complex structural elements also.

Right answer is (d) PID

For explanation I would say: FEM, MoM, FDTD are techniques used to know the Microstrip antenna PERFORMANCE. PI, PD, PID are CONTROL system mechanisms. MoM (Method of MOMENTS) is used to SOLVE the MIXED potential integrated equations obtained from the electromagnetic properties.

Correct option is (a) MICROSTRIP line feed

To explain: Microstrip line feed acts as an EXTENT to patch and is connected to patch just LIKE a CONDUCTING strip. In coaxial feed, inner conductor is attached to patch and OUTER conductor to ground plane. In Aperture coupling, two different substrates are separated by ground plane. In Proximity coupling, the length of stub and length to width ratio of patch controls the match.

Correct answer is (a) UHF and SHF

Explanation: SLOT antenna operates in the range of 300MHZ to 30GHz.

VLF-3 KHz – 30 KHz

MF- 300 KHz – 3MHz

UHF- 300 MHz-3GHz

SHF- 3 GHz -30 GHz

EHF- 30GHz-300GHz

So slot antenna operates at UHF and SHF range.

The correct answer is (a) High FREQUENCY structural stimulator

To explain I would say: HFSS is an Ansys TOOL used for the analysis of the antenna properties LIKE radiation and designing antenna. HFSS is acronym used for High frequency structural stimulator. HFSS is a commercial FEM solver for the ELECTROMAGNETIC structure of the antenna.

Right answer is (a) True

Best explanation: In Aperture coupling, TWO different substrates are separated by ground plane.This type of arrangement optimizes feed mechanism and RADIATING element. The ground plane is between the substrates and isolates feed from the radiating element and minimizes the interference DUE to SPURIOUS RADIATION.

The correct answer is (a) INNER CONDUCTOR is connected to patch and outer conductor to GROUND plane

The explanation: A coaxial feed CONSISTS of inner and outer conductors to which the patch and ground planes are attached respectively. In a Microstrip feed line the patch is attached to the feed like a conducting strip. Different substrates are used in APERTURE coupling.

Right choice is (a) Feed line

Easiest explanation: The feedline is sued to EXCITE to RADIATE the antenna in DIRECT or indirect way. There are mainly FOUR different types of feeding in Microstrip antenna: Microstrip line feed, COAXIAL probe, aperture coupling, proximity coupling.

The correct choice is (a) APERTURE TYPE

Explanation: Slot antenna belongs to the aperture antenna and operates at 300MHZ to 30GHz. Dipole is an example of Wire type. Reflector type example is Parabolic. Lens type: Convex-plane.

The correct ANSWER is (a) Microstrip antenna

Easy explanation: Microstrip antenna is a printed antenna. It is FABRICATED USING PHOTOLITHOGRAPHY technique. It is small in size and is used in mobile communication WIDELY. Horn, Yagi-Uda and Lens antennas are large in size.

Correct answer is (d) Proximity Coupling

Explanation: Proximity coupling feed PROVIDES largest BANDWIDTH. Microstrip LINE feed limits the bandwidth due to increase in SUBSTRATE thickness. Coaxial feed has NARROW bandwidth.

Right ANSWER is (a) True

Easiest explanation: The slot ANTENNA has low cross polarization COMPARED to PATCH antenna but its disadvantage is that it has bi-directional radiation which is corrected with the metallic cavity or REFLECTOR.

Right ANSWER is (d) Proximity Coupling

The best I can explain: In Proximity coupling, the length of stub and length to WIDTH ratio of patch controls the match. Microstrip line feed acts as an extent to patch and is connected to patch just like a conducting strip. In coaxial feed, inner conductor is attached to patch and outer conductor to GROUND plane. In APERTURE coupling, ground plane separates the different SUBSTRATES.

The correct option is (b) FEM

Easy explanation: HFSS is a HIGH Frequency STRUCTURAL Stimulator used as a commercial FEM solver for the electromagnetic properties of the ANTENNA. FEM and FDTD solve the partial differential equations while MOM is used to solve the mixed potential integrated equations obtained from the electromagnetic properties.