Microwave Devices Waveguides And AE

Question 1

Describe loop couplings

Answer 1

90• to H feilds at cavity wall

Question 2

Describe probe coupling with the E fields

Answer 2

Parallel to E feilds at the cavities centre

Question 3

Describe slot couplings

Answer 3

On the cavity wall with the wall currents across radiating slots

Question 4

Characteristics of a magnetron

Answer 4

Noisy
High gain
Narrow bandwidth

Question 5

Func a magnetron

Answer 5

High power oscillator in a radar Tx

Question 6

Func or a TWT

Answer 6

Amplifier in Transmitter and receivers

Question 7

Characteristics of TWT

Answer 7

High gain
Wide bandwidth
Low noise
Physical size

Question 8

Func of a Gunn diode

Answer 8

Local oscillator in Rx

Question 9

Characteristics of a Gunn diode

Answer 9

Electronically tuneable
Narrow bandwidth Low noise

Question 10

How is energy loss reduced in wave guides

Answer 10

Coat with silver
Pressure with nitrogen

Question 11

Purpose of the dummy load

Answer 11

To absorb microwave energy during servicing

Question 12

Describe choke flange

Answer 12

Creates an rf short circuit 1/2 wavelength from the end of the joint to prevent leaks

Question 13

Describe pencil beam

Answer 13

Narrow az & narrow elevation
Airborne interception

Question 14

Describe fan beam

Answer 14

Narrow in az & broad in elevation
Long range search

Question 15

Describe Cosec^2

Answer 15

Narrow az and broad el
Ground mapping

Question 16

types of radar AE

Answer 16

Parabolic reflectors
Slotted arrays
Active arrays

Question 17

Describe slotted planner array AE

Answer 17

Electronic beam mechanical steering

Question 18

Describe slotted phased array AE

Answer 18

Electronic beam electronic steering

Question 19

Describe active array

Answer 19

Lots of miniature txs and rxs fitted to the AE

Question 20

Purpose of T/R switch

Answer 20

Protects the receiver when transmitting prevents low power returns passing to the transmitter