Name of the College : Mahatma Gandhi University
Department : Communication Engineering
Subject Code/Name : MECCE 106-4/High Frequency Circuit Design
Sem : I Semester
Applicable For : 1st year Students
Website : mgu.ac.in
Document Type : Model Question Paper
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/mgu.ac.in/5061-MECCE%20106-4%20High%20Frequency%20Circuit%20Design.doc
MGU High Frequency Circuit Design Model Question
M.TECH DEGREE EXAMINATION :
Model Question Paper
Specialization: Communication Engineering
Related : MGU MECCE105-2 Antenna Theory & Design M.Tech Model Question Paper : www.pdfquestion.in/5060.html
First Semester :
MECCE 106-4 High Frequency Circuit Design
(Regular-2013 Admissions)
Time: Three Hours
Maximum: 100 marks
Answer all questions :
Each question carries 25 marks. :
1. a) Write a short note on propagation constant and phase velocity (6)
b) Derive the expression for input impedance of a terminated lossless line? (9)
c) The characteristics impedance of a lossless coaxial cable is 50H. The cable has length (3?/4). Determine the input impedance if output is (i) short circuited;
(ii) open – circuited. (10)
OR
2. a) Write a short note exponential taper. (5)
b) Using smith chart, Design a discrete two element matching networks that the Source impedance ZS= (50+j25) ? to the load ZL=(25-j50) ?. Assume a Characteristics impedance of 50 ? and operating frequency of f =2 GHz (10)
c) Design a double stub shunt tuner to match a load impedance ZL = (60-j80) ? to a 50 ? line. The stubs are to be short circuited stubs, and are spaced ?/8 apart. Assume that this load consists of a series resistor and capacitor, and the match frequency is 2 GHz. (10)
3. a) show the scheme to transform normalized low pass filter design RLC component values to band pass filter? (4)
b) Derive the expression for internal, external, and loaded quality factors for the standard series resonance circuits? (8)
c) Design a prototype low pass Butterworth filter that will provide at least 20dB attenuation at the frequency of f=2f3dB (13)
OR
4. a) Explain Kuroda’s identity (5)
b) (i) Design a low pass filter using discrete components, whose input and output are matched to a 50 ohm impedance and that meets the following specifications: cutoff frequency of 3Ghz; equiripple of .5dB; and rejection of at least 40dB at approximately twice the cut off frequency. Assume a dielectric material that results in aphase velocity of 60%of the speed of light. (7)
(ii) Implement micro strip equivalent of the above filter. (13)
5. a) Discuss about the High power amplifiers. (4)
b) Derive the expressions for Power relationship of a RF power amplifier? (12)
c) An RF amplifier has the following S parameters .
The input side of the amplifier is connected to a voltage source with Vs=5V<00 and source impedance Zs=40 ohms.The output is utilized to derive an antenna which has an impedence of ZL=73 ohms.
Assume that the S parameters of the amplifier are measured with reference to a Z0 =50 ohms characteristics impedence, find the following quantities: tranducer gain, unilateral transducer gain,operating power gain (9)
OR
6. a) Draw the general input and output stability circles denoting the stable and unstable regions (5)
b) Derive the stability factor k. (10)
c) A MESFET operated at 5.7 GHz has the following S parameters (10)
(i) Check whether the circuit is unconditionally stable or not
(ii) Find the maximum power gain under optimal choice of the reflection coefficients, assuming the unilateral design(S12=0)
7. a) Explain YIG Oscillator (6)
b) Derive the high frequency oscillation conditions. (9)
c) Derive the expression for series and parallel resonant frequency of quartz oscillator. (10)
OR
8. a) Explain the frequency domain considerations of a mixer. (6)
b) Explain the design of a single ended mixer (9)
c) An RF channel with a centre frequency of 1.89GHz and Bandwidth of 20 MHz is to be down converted to an IF of 200MHz. Select an appropriate fLO. Find the quality factor Q of a Band pass filter to select this channel if no down conversion is involved, and determine the Q of a band pass filter after down conversion (10)