This set of RF & Microwave Circuit Design Multiple Choice Questions & Answers (MCQs) focuses on “Dielectric Resonator Oscillators”.

1. In oscillator tuning circuits, dielectric resonators are preferred over waveguide resonators because:

a) they have high Q factor

b) compact size

c) they are easily integrated with microwave integrated circuits

d) all of the mentioned

2. A dielectric resonator coupled with an oscillator operates in:

a) TE_{10δ}

b) TE_{01δ}

c) TM_{10δ}

d) TM_{01δ}

3. The stability of an oscillator is enhanced with the use of:

a) high Q tuning network

b) passive elements

c) appropriate feedback methods

d) none of the mentioned

4. A dielectric resonator is modeled as __________ when it is used as a tuning circuit with a oscillator.

a) series RLC circuit

b) parallel RLC circuit

c) LC circuit

d) tank circuit

5. If the reflection coefficient seen on the terminated microstrip line looking towards the resonator is 0.5, then the coupling coefficient is:

a) 0.5

b) 0.25

c) 0.234

d) 1

6. It is desired to design a frequency oscillator at 2.4 GHz and the reflection coefficient desired is 0.6, then the coupling coefficient between the feed line and the dielectric resonator is:

a) 1.5

b) 1

c) 0.5

d) none of the mentioned

7. The coupling factor between the resonator and the microstrip line is the ratio of external Q to the unloaded Q.

a) true

b) false

8. A dielectric resonator can be incorporated into a circuit to provide _________ using either parallel or series arrangement.

a) frequency stability

b) oscillations

c) high gain

d) optimized reflection coefficient

9. 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:

a) 50 Ω

b) 12.5 Ω

c) 25 Ω

d) none of the mentioned

10. If the equivalent impedance of the resonator at resonance is 12.5 Ω and the characteristic impedance of the feed line is 50 Ω, then the coupling coefficient is:

a) 0.25

b) 0.5

c) 0.75

d) 1