Microwave Engineering Online Test

1. For a unilateral device condition for unconditional stability in terms of S parameters is:

2. _________ has a constant power spectral density.

3. If the reflection coefficient between the feed line and the resonator is -0.6, then the equivalent impedance of the resonator at resonance given that the characteristic impedance of the microstrip line is:

4. If p=0.3 and the wave number of air in TM mode is 16, then the intrinsic impedance of air in TM mode given wave number is 125 is:

5. Varactor diodes are operated in _________ region to achieve maximum efficiency possible.

6. The wave impedance for a non-propagating mode in TE mode is:

7. For a Wilkinson power divider of insertion loss L and the coupler is matched to the external circuitry, and then the gain of the coupler in terms of insertion loss is:

8. For a circular waveguide in TM11 mode of propagation with inner radius of 30mm, and the phase constant being equal to 0.3, then the wave impedance is equal to:

9. Coupled line couplers are:

10. For a lossy transmission line, γ=0.02+j0.15 and is 20m long. The line is terminated with an impedance of a 400Ω. Then the input impedance of the transmission line given that the characteristic impedance of the transmission line is 156.13+j11.38Ω is:

11. The amount of power by which the received power must be greater than the threshold level required to maintain a minimum quality of service is called _______

12. Complex load impedance can be converted to real load impedance by:

13. The S₂₁ parameter of a HJT increases with increase in the operating frequency of the transistor.

14. If the outer circumference and the inner circumference of a transmission line are 40π and 25π units respectively, then the capacitive reactance of the coaxial transmission line is:

15. If the length of the intrinsic region in IMPATT diode is 2 µm and the carrier drift velocity are 10⁷ cm/s, then the nominal frequency of the diode is:

16. Major advantage of a quarter wave transformer is:

17. The relation between unloaded Q and external Q is:

18. Admittance and impedance matrices of a micro waves network are related as:

19. If the reflection coefficient for transmission line is 0.24, then the return lossin dB is:

20. For a two port network the voltage reflection coefficient seen looking towards the load, Г_S is:

21. The element of a Z matrix, Z_ij can be given in terms of voltage and current of a microwave network as:

22. In transistor oscillators, the requirement of a negative resistance device is satisfied using a varactor diode.

23. Quality factor of a coaxial cable transmission line is independent of the medium between the wires of the transmission line.

24. Input impedance of a short circuited transmission line is :

25. Passband characteristics of tapered lines differ from one type of taper to another.

26. If a transmission line of zₒ=50Ω is matched using λ/4 transmission line of z₁=100Ω, then the transmission co efficient T₂ is:

27. The one below is the only micro wave network element that is a TEM line:

28. The metalized substrate is coated with __________ covered with the mast and exposed to light source.

29. with the increase in the operating frequency of a BJT, the S₂₂ parameter of the transistor:

30. An antenna has a field pattern of E (θ) = cos2 θ, θ varies between 0 and 900. Half power beam width of the antenna is:

31. Equivalent noise temperature associated with an arbitrary white noise source is:

32. Ferrite isolators are ____ port microwave devices.

33. Power amplifiers in the increasing order of efficiency is:

34. The level of coupling required between a resonator and its attached circuitry is a standard and independent of the application where coupling is required.

35. The major disadvantage of coupled line coupler is:

36. The power delivered to the input port of a resistive power divider is equal to the source voltage applied.

37. Bandwidth of balanced amplifier can be an octave or more, but is limited by the bandwidth of the coupler.

38. If the third order input intercept point of a mixer is 13 dBm and if the mixer has a conversion loss of 6 dBm, then the third order intercept point at the output is:

39. Insertion loss is the power delivered to the through port.

40. When the input frequency consists of more than one closely spaced frequency, it results in:

41. Gain of a parametric amplifier in terms of the frequencies involved in their operation is:

42. GPS operates at a single frequency band.

43. Link margin that is used to account for fading effects is called fade margin.

44. If the normalized input impedance of a transmission line is 0.5 Ω, then he reflection coefficient of a ƛ/2 transmission line is

45. A source has a radiation intensity pattern given by U=U_M sin θ. The directivity of the source with this power pattern is:

46. The plot of input impedance magnitude v/s frequency has a peak at the resonant frequency.

47. In the course of development of microwave circuits, two distinct types of microwave integrated circuits have been developed according to the application requirements.

48. Lumped elements can be used to make resonators that rare to be operated at microwave frequencies.

49. If the beam width of an antenna in two orthogonal planes are 30⁰ and 60⁰. Then the directivity of the antenna is:

50. The losses that occur in a transmission line is: