০১। A (75 - J50) ohm load is connected to a coaxial of Z0 = 75 ohm at 10 GHz. The best method of matching is to connect
ক) an inductance at load
খ) a short circuited stub at load
গ) a short circuited stub at specific distance from load
ঘ) a capacitance at specific distance from load
০২। A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is
ক) 4000 Ω
খ) 400 Ω
গ) 40 Ω
ঘ) 4 Ω
০৩। A 3 port circulator is in the given figure. Its scattering matrix is
ক)
খ)
গ)
ঘ)
০৪। A 75 ohm line is first short terminated and minima locations are noted. Then the short is replaced by resistive load and minima location are again noted. If minima location are not altered and VSWR is 3, the value of resistive load is
ক) 25 Ω
খ) 50 Ω
গ) 225 Ω
ঘ) 250 Ω
০৫। A balun should have
ক) low SWR at both ports
খ) high SWR at both ports
গ) high SWR at input port and low SWR at output port
ঘ) low SWR at input port and high SWR at output
০৬। A branched duplexer requires
ক) TR tubes
খ) ATR tube
গ) both TR and ATR tube
ঘ) none of the above
০৭। A cavity resonator is
ক) a hollow metallic enclosure
খ) a hollow enclosure having magnetic material as its walls
গ) a hollow enclosure having dielectric material as its walls
ঘ) either (b) or (c)
০৮। A circular polarizer converts a linearly polarized wave into a circularly polarised wave.
ক) True
খ) False
০৯। A circular waveguide carries TE11 mode whole radial electric field is given by Er = E0j1(r) sin Φ V/m where r is radial distance in cm from the axis The cut off wavelength is
ক) 10 cm
খ) 3 p cm
গ) 2 p cm
ঘ) 8 cm
১০। A circular waveguide has an infinite set of TE and TM modes.
ক) True
খ) False
১১। A coaxial line has L = 500 nH/m and C = 50 pF/m. The characteristic impedance is
ক) 500 Ω
খ) 250 Ω
গ) 100 Ω
ঘ) 50 Ω
১২। A coaxial RF cable has a characteristic impedance of 50 Ω and C equal to 40 pF/m. The inductance is
ক) 1 μ H/m
খ) 10 μ H/m
গ) 0.1 μ H/m
ঘ) 0.01 μ H/m
১৩। A directional coupler is used
ক) to transmit microwave signals
খ) to generate microwave signals
গ) to measure amplitude and phase of a travelling wave
ঘ) both (a) and (b)
১৪। A directional coupler is used to determine
ক) r v
খ) r v and VSWR
গ) L and C
ঘ) wave velocity
১৫। A disadvantage of microstrip line as the connections of compared to strip line is that former
ক) do not lend themselves to printed circuit
খ) are more likely to radiate
গ) are bulky
ঘ) are more expensive and complex
১৬। A duplexer is used to
ক) couple two antennas to a transmitter
খ) isolate the antenna from the local oscillator
গ) prevent interference between two antennas connected to receiver
ঘ) use an antenna for reception or transmission without interference
১৭। A klystron amplifier generally uses Pierce gun
ক) True
খ) False
১৮। A line has a phase constant of 29.8 rad/m. At 1000 MHz the wavelength is
ক) 29.8 m
খ) 2.98 m
গ) 2.1 m
ঘ) 0.21 m
১৯। A line has an attenuation of 0.054 Np/m. The attenuation in decibels is
