Question

Question 3. When a screw is inserted in the top of a waveguide system operating in the TE10 mode, it is noticed that this will introduce a VSWR varying from unity to 3.0 for the full range of depth of insertion. That is, with the screw out, the ne; when the screw protrudes the maximum amount, the VSWR is 3.0. (a) If one thinks of the screw as giving rise to the equivalent of shunt capacitive loading, what is the corresponding range of adjustment in the equivalent per- unit reactance X/Z.? (b) Assuming the screw can be placed any arbitrary distance from the load, note on a Smith chart the range of load impedance which may be matched with this device. (20 marks)

Answer 1

question 3a)
If y be the reeflection coffficient. then foto do where x = so Terminal load X-% to = chareaclireishes impedence. And Uswa= 1411 1+ the Heli-x-2 xto . a 2x x tho 2 Lo xtho VSWR 2 Giren that uswr is 1 when & the screen is out VSWR = 3 when screw is entered so √ varies from 1 to 3.
question 3b)
Ba from the above calculation of VSWR be belweek I to 3. resistance Suppose we have an impedance of 100 ohm. and inductive reactanos . 100 ohm. So Z=100 + 1001 = the impedance. te but loon to the prime centre of smith chart. So the dormalized impedance 2011 oj 1.041.07 90+ 27 / 0 120 Smith chart of impedance plotting .0%