Category: Microwave Engineering Objective Questions

250+ TOP MCQs on Quarter Wave Transformer and Answers

Microwave Engineering Multiple Choice Questions on “Quarter Wave Transformer”.

1. If a transmission line of characteristic impedance 50 Ω is to be matched to a load of 100Ω, then the characteristic impedance of the ƛ/4 transmission line to be used is:
A. 70.71 Ω
B. 50 Ω
C. 100 Ω
D. 75 Ω
Answer: A
Clarification: When a transmission line is not terminated with a matched load, it leads to losses and reflections. In order to avoid this, a λ/4 transmission line can be used for matching purpose. The characteristic impedance of the λ/4 transmission line is given by Z1=√(ZₒR)L. substituting the given values, we get Z1=70.71 Ω.

2. If a λ/4 transmission line is 100Ω is used to match a transmission line to a load of 100Ω, then the characteristic impedance of the transmission line is:
A. 100 Ω
B. 50 Ω
C. 70.71 Ω
D. 200 Ω
Answer: A
Clarification: When a transmission line is not terminated with a matched load, it leads to losses and reflections. In order to avoid this, a λ/4 transmission line can be used for matching purpose. The characteristic impedance of the λ/4 transmission line is given by Z1=√(ZₒR)L. substituting the given values,
Z0=100 Ω.

3. Expression for the characteristic impedance of a transmission line(λ/4) used for impedance matching is:
A. Z1=√(ZₒR)L
B. Z1=√(Zₒ/R)L
C. Z1=√(Zₒ+R)L
D. None of the mentioned
Answer: A
Clarification: When a transmission line is not terminated with a matched load, it leads to losses and reflections. In order to avoid this, a λ/4 transmission line can be used for matching purpose. Hence the expression used to find the characteristic impedance of the λ/4 transmission line is Z1=√(ZₒR)L.

4. If there is no standing wave on a transmission line, then the value of SWR is:
A. 1
B. 0
C. Infinity
D. Insufficient data
Answer: A
Clarification: When there are no standing waves in the transmission line, the reflection co-efficient is zero and hence input impedance of the transmission line is equal to the characteristic impedance of the line. Hence the relation between SWR and reflection co-efficient yields SWR as 1.

5. When a λ/4 transmission line is used for impedance matching, then which of the following is valid?
A. Standing waves are present on the λ/4 transmission line
B. No standing waves on the λ/4 transmission line
C. Standing waves are not present both on the feed line and the matching λ/4 line
D. Standing waves are present on both the feed line and the matching λ/4 line
Answer: A
Clarification: λ/4 transmission line is used to match the load impedance to the characteristic impedance of the transmission line. Hence, standing waves are present on the λ/4 transmission line, but not on the transmission line since it is matched

6. For a transmission line , if the input impedance of the transmission line is 100Ω with a characteristic impedance of 150Ω, then the magnitude of the reflection co efficient:
A. 0.5
B. 1
C. 0.2
D. 0
Answer: C
Clarification: The expression for reflection co-efficient of a transmission line in terms input and characteristic impedance is (Zin-Zₒ)/(Zin+ Zₒ). Substituting the given values in the above expression, reflection co-efficient is 0.2.

7. If the reflection co-efficient of a transmission line is 0.334 with a characteristic impedance of 50Ω then the input impedance of the transmission line is:
A. 100 Ω
B. 50 Ω
C. 150 Ω
D. None of the mentioned
Answer: A
Clarification: Substituting the given voltage reflection co-efficient and the characteristic impedance of the transmission line in ┌= (Zin-Zₒ)/(Zin+ Zₒ). The input impedance of the transmission line is 100Ω

8. When a transmission line of characteristic impedance(50Ω) zₒ is matched to a load by a λ/4 transmission line of characteristic impedance 100Ω, then the transmission co efficient is:
A. 1.5
B. 0.5
C. 1.333
D. 2
Answer: C
Clarification: When a transmission line is matched to a load by using a λ/4 transmission line, the transmission co-efficient T1 of the line is obtained using the expression 2Z1/ (Z1+Z0). Here Z1 is the characteristic impedance of the λ/4 transmission line and Z1 is the characteristic impedance of the transmission line. Substituting the given values, we get T1=1.3333.

9. If a transmission line of zₒ=50Ω is matched using λ/4 transmission line of z₁=100Ω, then the transmission co efficient T₂ is:
A. 1
B. 0.6667
C. 1.3333
D. 2
Answer: B
Clarification: When a transmission line is matched to a load by using a λ/4 transmission line, the transmission co-efficient T2 of the line is obtained using the expression 2Z0/ (Z1+Z0). Here Z1 is the characteristic impedance of the λ/4 transmission line and Z0 is the characteristic impedance of the transmission line. Substituting the given values, we get T2=0.6667.

10. If the transmission co-efficient T₁ of a transmission line is 1.333 and the characteristic impedance of the λ/4 transmission line used is 100Ω, then the characteristic impedance of the transmission line is:
A. 50Ω
B. 100Ω
C. 70.71Ω
D. None of the mentioned
Answer: A
Clarification: Expression for transmission co-efficient of a transmission line matched using a λ/4 transmission line is 2Z1/ (Z1+Z0). Substituting the known values, the characteristic impedance of the transmission line is 50Ω.


Microwave Engineering,

250+ TOP MCQs on Single Stub Matching and Answers

Microwave Engineering Multiple Choice Questions on “Single Stub Matching”.

1. The major advantage of single stub tuning over other impedance matching techniques is:
A. Lumped elements are avoided
B. It can be fabricated as a part of transmission line media
C. It involves two adjustable parameters
D. All of the mentioned

Answer: D
Clarification: Single stub matching does not involve any lumped elements, it can be fabricated as a part of transmission media and it also involves to adjustable parameters namely length and distance from load giving more flexibility.

2. Shunt stubs are preferred for:
A. Strip and microstrip lines
B. Coplanar waveguides
C. Circular waveguide
D. Circulators

Answer: A
Clarification: Since microstrip and strip lines are simple structures, impedance matching using shunt stubs do not increase the complexity and structure of the transmission line. Hence, shunt stubs are preferred for strip and microstrip lines.

3. The two adjustable parameters in single stub matching are distance‘d’ from the load to the stub position, and _________
A. Susceptance or reactance provided by the stub
B. Length of the stub
C. Distance of the stub from the generator
D. None of the mentioned

Answer: A
Clarification: Reactance or susceptance of the matching stub must be known before it used for matching, since it is the most important parameter for impedance matching between the load and the source.

4. In shunt stub matching, the key parameter used for matching is:
A. Admittance of the line at a point
B. Admittance of the load
C. Impedance of the stub
D. Impedance of the load

Answer: A
Clarification: In shunt stub tuning, the idea is to select d so that the admittance Y, seen looking into the line at distance d from the load is of the form Yₒ+jB. Then the stub susceptance is chosen as –jB, resulting in a matched condition.

5. For series stub matching, the parameter used for matching is:
A. Impedance of the transmission line at a point
B. Voltage at a point on the transmission line
C. Admittance at a point on the transmission line
D. Admittance of the load

Answer: A
Clarification: In series sub matching, the distance‘d’ is selected so that the impedance, Z seen looking into the line at a distance‘d’ from the load is of the form Zₒ+jX. Then the stub reactance is chosen as –jX resulting in a matched condition.

6. For co-axial lines and waveguides, ________ is more preferred.
A. Open circuited stub
B. Short circuited stub
C. Slotted section
D. Co-axial lines cannot be impedance matched

Answer: B
Clarification: For co-axial cables and waveguides, short-circuited stub is usually preferred because the cross-sectional area of such an open-circuited line may be large enough to radiate, in which case the stub is no longer purely reactive.

7. For a load impedance of ZL=60-j80. Design of 2 single-stub shunt tuning networks to match this load to a 50Ω line is to be done. What is the normalized admittance obtained so as to plot it on smith chart?
A. 1+j
B. 0.3+j0.4
C. 0.4+j0.3
D. 0.3-j0.4

Answer: B
Clarification: To impedance match a load to a characteristic impedance of the transmission line, first the load has to be normalized. That is, zL=ZL/Z0. For impedance matching using shunt stubs, admittance is used. Taking the reciprocal of impedance, normalized load admittance is 0.3+j0.4.

8. If the normalized admittance at a point on a transmission line to be matched is 1+j1.47. Then the normalized susceptance of the stub used for shunt stub matching is:
A. 1Ω
B. 1.47 Ω
C. -1.47 Ω
D. -1 Ω

Answer: C
Clarification: When shunt stubs are used for impedance matching between a load and transmission line, the susceptance of the shunt stub must be negative of the line’s susceptance at that point for impedance matching.

9. After impedance matching, if a graph is plot with frequency v/s reflection co-efficient of the transmission line is done, then at the frequency point for which the design is done, which of the following is true?
A. There is a peak at this point of the curve
B. There is a dip at this point of the curve
C. The curve is a straight line
D. Such a plot cannot be obtained

Answer: B
Clarification: Since the plot is frequency v/s reflection co-efficient, after impedance matching the reflection co-efficient will be zero or minimum. Hence, there is a dip at that point of the curve.

10. In series stub matching, if the normalized impedance at a point on the transmission line to be matched is 1+j1.33. Then the reactance of the series stub used for matching is:
A. 1 Ω
B. -1.33 Ω
C. -1 Ω
D. 1.33 Ω

Answer: B
Clarification: The reactance of the series stub is negative of the reactance of the line at the point at which it has to be matched. That is, if the line reactance is inductive, the series stub’s reactance is capacitive.

250+ TOP MCQs on Quadrature Hybrid and Answers

Microwave Engineering Multiple Choice Questions on “Quadrature Hybrid”.

1. Quadrature hybrids are those couplers which are:
A. 3 dB couplers
B. Directional couplers
C. They have a 900 phase difference between signals in through and coupled arms.
D. All of the mentioned
Answer: D
Clarification: Quadrature hybrids are directional couplers that have a phase difference of 900 between the signals obtained at through and coupled ports.

2. Branch-line couplers are also popular as Quadrature hybrids.
A. True
B. False
Answer: A
Clarification: Quadrature hybrids are also called as branch-line couplers. The other 3 dB couplers are coupled line couplers or Lange couplers. These couplers also can be Quadrature hybrids.

3. The S matrix of a Quadrature hybrid is of size 4×4 and the diagonal elements of a matched coupler are all:
A. 1
B. 0
C. Cannot be determined
D. None of the mentioned
Answer: B
Clarification: In a matched coupler, since all ports are matched, no power goes back to the port from which the flow of energy in the coupler occurred. Since the backward power flow is zero for matched network, the diagonal elements are zero.

4. A branch-line coupler is an asymmetric coupler.
A. True
B. False
Answer: B
Clarification: A branch-line coupler is a symmetric coupler that has all four ports placed symmetrically. Since the construction is symmetric, any port can be used as input and any port can be used as output.

5. Branch-line couplers are preferably made using waveguides so as to obtain high gain and simple construction.
A. True
B. False
Answer: B
Clarification: Branch-line couplers are mostly done using microstrip lines. They also reduce the complexity of the circuit and can be easily integrated with other microwave devices in all large scale applications.

6. A 50 Ω branch-line Quadrature hybrid has to be designed to operate over a range of frequencies. The branch-line impedance of this coupler so designed is:
A. 70.7 Ω
B. 35.4 Ω
C. 50 Ω
D. 100 Ω
Answer: B
Clarification: Each arm of a Quadrature hybrid is λ/4 long; λ is the wavelength at which the coupler is designed to operate. The branch-line impedance for a λ/4 line is Z0/√2. Substituting for Z0 in the equation, the impedance is 35.4 Ω.

7. The plot S11 v/s frequency for a branch-line coupler has a straight line characteristic for a wide range of frequency around the designed frequency range.
A. True
B. False
Answer: B
Clarification: S11 parameter signifies the power measured at port 1 when port 1 is used as an input port. When the ports of the coupler are matched, no power is reflected back to the port 1. Hence S11 curve has a dip at the frequency for which the coupler was operated to design. A fall and rise in the curve is seen at this point.

8. The curve of S14 for a branch-line coupler is similar to that of the S11 curve of the branch-line coupler.
A. True
B. False
Answer: A
Clarification: S14 parameter gives the power measured at the port 4 or the isolated port of the branch-line coupler. Since the signals that reach port 4 from 2 different arms are 900 out of phase with each other, theoretically power at port 4 is zero. Practically, it is zero for the designed frequency but some power is received at other frequencies.

9. S12 and S13 curves for branch-line couplers are almost a straight line parallel to X –axis. Both the curves are similar and follow same path.
A. True
B. False
Answer: A
Clarification: S13 and S12 parameters give the power measured at port 2 and port 3 of the branch-line coupler when port 1 is used as the input port. Since these are the through and coupled ports, power measured across these ports is almost constant and resemble a straight line parallel to X axis.

10. If the branch-line impedance of a coupler designed to operate at 1 GHz is 70.70 Ω, then the characteristic impedance of the material of the arms of the branch-line coupler is:
A. 70.7 Ω
B. 50 Ω
C. 100 Ω
D. None of the mentioned
Answer: C
Clarification: Given the branch impedance is 70.70 Ω; the characteristic impedance of the line is Z√2. This relation is used since all the arms of a branch-line coupler are λ/4 long. Substituting for Z, the characteristic impedance of the line is 100 Ω.


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250+ TOP MCQs on Applications of RF Diodes and Answers

Microwave Engineering Multiple Choice Questions on “Applications of RF Diodes”.

1. Classical p-n junction diode cannot be used for high frequency applications because of:
A. High bias voltage
B. High junction capacitance
C. Frequency sensitive
D. High forward biased current
Answer: B
Clarification: p-n junction diodes have high junction capacitance that makes them not suitable for high frequency applications. A Schottky barrier diode relies on a semiconductor metal junction and hence making them suitable for high frequency application.

2. Schottky barrier diode is a sophisticated version of the point contact ______________
A. Germanium diode
B. Silicon crystal diode
C. GaAs diode
D. None of the mentioned
Answer: B
Clarification: Schottky barrier diode is a sophisticated version of the point contact silicon crystal diode, wherein the metal-semiconductor junction so formed is a surface rather than a point contact as it is in point contact silicon crystal diode.

3. Advantage of Schottky diode over silicon crystal diode is the presence minority charge carriers.
A. True
B. False
Answer: B
Clarification: The advantage of Schottky diode over point contact silicon crystal diode is the elimination of minority carrier flow in the reverse biased condition of the diode. Due to the elimination of holes, there is no delay due to hole-electron recombination and hence operation is faster.

4. As the area of rectifying contact goes on increasing, the forward resistance of the Schottky diode:
A. Increases
B. Decreases
C. Remains unchanged
D. None of the mentioned
Answer: B
Clarification: The noise and forward resistance of Schottky diode is small as compared to the noise figure and forward resistance of point contact silicon crystal diode. Hence, as the area of rectifying contact goes on increasing, the forward resistance decreases.

5. The number of semiconductor layers in a TRAPATT diode is:
A. Two
B. Three
C. Four
D. One
Answer: B
Clarification: Silicon is usually used for the manufacture of TRAPATT diodes and they have a configuration p+ nn+ the p-N junction is reverse biased beyond the breakdown region, so that the current density is larger.

6. In order to achieve high current density, a compromise in _______is made in a TRAPATT diode.
A. Gain
B. Size
C. Operating frequency
D. No compromise is made on any of the parameter
Answer: C
Clarification: When a high current density achieved, it decreases the electric field in the space charge region and increases the carrier transit time. Due to this, the frequency of operation gets lowered to less than 10 GHz. But efficiency is increased due to low power dissipation.

7. TRAPATT diode is normally mounted at a point inside a coaxial resonator where there is minimum RF voltage swing.
A. True
B. False
Answer: B
Clarification: Inside a coaxial resonator, the TRAPATT diode is normally mounted at a point where maximum RF voltage swing is obtained. When the combined DC bias and RF voltage exceeds breakdown voltage, avalanche occurs and a plasma of holes and electrons are generated which get trapped.

8. A major disadvantage of TRAPATT diode is:
A. Fabrication is costly
B. Low operational bandwidth
C. Low gain
D. High noise figure
Answer: D
Clarification: The disadvantages of TRAPATT diode are high noise figure and generation of strong harmonics due to the short duration of the current pulse. Since short duration of current pulses are used, they find application in S band pulse transmitters.

9. _________ gives a frequency domain representation of a signal, displaying the average power density versus frequency.
A. CRO
B. Oscilloscope
C. Spectrum analyzer
D. Network analyzer
Answer: C
Clarification: Spectrum analyzer gives a frequency domain representation of a signal, displaying the average power density versus frequency. Thus, its function is dual to that of oscilloscope, which displays the time domain representation of a signal.

10. The most important functional unit of a spectrum analyzer is:
A. Mixer
B. IF amplifier
C. Sensitive receiver
D. None of the mentioned
Answer: C
Clarification: A spectrum analyzer basically consists of a sensitive receiver that tunes over a specified frequency band and gives out a video output that is proportional to the signal power in a narrow bandwidth.

11. A tunnel diode is a p-n junction diode with a doping profile that allows electron tunneling through a narrow energy band gap.
A. True
B. False
Answer: A
Clarification: A tunnel diode is a pn junction diode with a doping profile that allows electron tunneling through a narrow energy band gap leading to negative resistance at high frequencies. Tunnel diode can be used for both oscillators and amplifiers.


Microwave Engineering,

250+ TOP MCQs on Dielectric Resonator Oscillators and Answers

Microwave Engineering Multiple Choice Questions on “Dielectric Resonator Oscillators”.

1. 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
Answer: A
Clarification: The stability of an oscillator is enhanced with the use of high Q tuning circuits. At microwave frequencies, lumped elements cannot provide high Q factor. Waveguide tuning circuits cannot be integrated with small microwave circuits easily. Hence dielectric resonators are used to provide high Q factor.

2. 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
Answer: D
Clarification: Dielectric resonators have all the above properties mentioned. Also, they are made of ceramic materials which also increases the temperature stability of resonator which further increases the fields of application.

3. A dielectric resonator coupled with an oscillator operates in:
A. TE10δ
B. TE01δ
C. TM10δ
D. TM01δ
Answer: A
Clarification: A dielectric resonator is coupled to an oscillator by positioning it in close proximity to a microstrip line. The resonator operates in TE10δ mode, and couples to the fringing field magnetic field of the microstrip line.

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
Answer: B
Clarification: The strength of coupling between a microstrip line and the resonator is determined by the spacing between them. The resonator appears as a series load on the microstrip line. The resonator is modeled a s a parallel RLC circuit and the coupling to the feed line is modeled by the turns ratio of the transformer.

5. The coupling factor between the resonator and the microstrip line is the ratio of external Q to the unloaded Q.
A. true
B. false
Answer: B
Clarification: The coupling factor the resonator and the microstrip line is the ratio of unloaded Q to external Q. The simplified expression for coupling factor is N2R/2Z0.

6. 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
Answer: D
Clarification: Coupling coefficient for a line in terms of reflection coefficient is Г/ (1-Г). Substituting the given reflection coefficient in this expression, the coupling coefficient is 1.

7. 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
Answer: A
Clarification: Oscillators can be obtained in various transistor configurations, their instability can be enhanced by using series or shunt elements. A dielectric resonator can be incorporated into a circuit to provide frequency stability using either parallel or series arrangement.

8. 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
Answer: A
Clarification: Coupling coefficient for a line in terms of reflection coefficient is Г/ (1-Г). Substituting the given reflection coefficient in this expression, the coupling coefficient is 1.5.

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
Answer: B
Clarification: The equivalent impedance of the resonator at resonance is Z0 (1 + Г)/(1- Г). Substituting the given values in this expression, equivalent impedance of the resonator is 12.5 Ω.

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
Answer: A
Clarification: Coupling coefficient is defined as the ratio of the equivalent impedance of the resonator to the characteristic impedance of the feed line. Substituting accordingly, coupling coefficient is 0.25.


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250+ TOP MCQs on Generator And Load Mismatches and Answers

Microwave Engineering Multiple Choice Questions on “Generator And Load Mismatches”.

1. When a load is matched to a transmission line, the condition that is satisfied when matched is:
A. ZL=Z0
B. ZL=2Z00
C. ZL=Zin
D. ZL=2Zin
Answer: A
Clarification: In order to deliver the maximum power from source to load, the transmission line has to be matched to the load. Hence for the transmission line to be matched to the load, the condition to be satisfied is ZL=Z0.

2. When a load ZL is matched to a line, the value of standing wave ratio is:
A. 1
B. 0
C. infinity
D. insufficient data to calculate SWR
Answer: A
Clarification: When the load is matched to the transmission line, they are said to be matched. Hence standing waves exist on the transmission line. Hence SWR is 1.

3. The value of reflection co efficient when a transmission line is matched to the load is:
A. 1
B. 0
C. 0.707
D. cannot be determined
Answer: B
Clarification: When the transmission line and the load are matched, no reflections occur in the transmission line and hence no voltage wave is reflected back. Hence, the reflection co-efficient for a matched line is 0.

4. The value of transmission co efficient when a transmission line is matched to a load is:
A. 1
B. 0
C. 0.5
D. 0.707
Answer: A
Clarification: Transmission co-efficient is defined as the ratio of the incident power to transmitted power at the load end. When the transmission line is matched, the incident power is completely transmitted. Hence, transmission co-efficient is 1.

5. The expression for power delivered to a load , when a line is matched and supplied with a source of Vg with generator impedance Rg +jXg is:
A. 0.5*Vg2/Rg
B. 0.5*Vg2Rg/4(Rg2+ Xg2)
C. Rg/4(Rg2+ Xg2)
D. generator impedance does not cause any losses
Answer: B
Clarification: Due to the generator impedance, there will be some power dissipated and hence the total source power is not transmitted. Hence that power dissipated due to generator impedance is also removed from the total power delivered.

6. If a transmission line is exited from a source of 4V at 1.2GHz frequency with a generator impedance of 4+j3 with a characteristic impedance of the transmission line 50Ω,then the power delivered to the load is:
A. 0.1 watt
B. 0.9 watt
C. 0.8 watt
D. 1watt
Answer: C
Clarification: The expression for total power delivered given the generator impedance is 0.5*Vg2Rg/4(Rg2+ Xg2). Substituting the given values in the above equation, the total power delivered is 0.8 watt.

7. If the generator impedance of a source connected to a transmission line is 50+j100Ω, then for conjugate matching to occur , the input impedance must be:
A. 50-j100 Ω
B. 50+100 Ω
C. 50 Ω
D. one of the mentioned
Answer: A
Clarification: The condition for conjugate matching is Zin=*Zg, where Zin is the input impedance of the transmission line and Zg is the generator impedance. For conjugate matching, taking the conjugate of the given impedance, the input impedance must be 50-100j Ω.

8. After conjugate impedance matching the input impedance used for matching after normalization was 1+j with the characteristic impedance of the transmission line being 100Ω, then the generator impedance must have been:
A. 100+100j
B. 1+j
C. 100-100j
D. 1-j
Answer: C
Clarification: After conjugate matching the input impedance of a transmission line after normalization is 1+j. hence the generator impedance will be the conjugate, that is 1-j. multiplying with the characteristic impedance, we get 100-100j.

9. For a matched transmission line with a generator impedance of 50Ω and the source being 4V,1GHZ,then the maximum power delivered to the line is:
A. 0.4 watt
B. 0.04 watt
C. 0.5 watt
D. no power is delivered
Answer: B
Clarification: The maximum power delivered to the load given the generator impedance is 0.5*Vg2Rg/4(Rg2+ Xg2). Substituting in the above equation the given values, power delivered is 0.04 watt.

10. If the power delivered to a load is 0.04w, then the normalized generator impedance if the source use is 4V at 2GHz and the generator impedance is real and characteristic impedance of the transmission line is 50Ω is:
A. 1 Ω
B. 1+j Ω
C. 1-j Ω
D. 50 Ω
Answer: A
Clarification: The maximum power delivered to the load given the generator impedance is 0.5*Vg2Rg/4(Rg2+ Xg2). Rearranging the equation and substituting the given value, Rg is 50Ω. To normalize, dividing the impedance by characteristic impedance, the impedance is 1 Ω.


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