62802. A short circuited stub is preferred to an open circuited stub because an open circuited stub
62803. If the peak transmitted power in a radar is increased by a factor 81, the maximum range is increased by a factor of
62804. Radar is essentially an echo ranging system
62805. In Gunn diode electrons are transferred from
62806. Consider the following statements about radar Beacon It is also called transponder.It includes pulse transmitter, receiver and antenna.It replies with full power even when the signal receives is weak. Which of the above statements are correct?
62807. Consider the following statements about instrument landing system of aircraft It ensures correct landing under conditions of low visibility.It consists of runaway localizer, glide path equipment and marker beacons.It is basically a blind landing system. Which of above statements are correct?
62808. Effect of loading of line is
62809. Which mode has the minimum cutoff frequency in rectangular wave guides?
62810. As compared to dimensions of most feeds, the skin depth at microwave frequencies is
62811. In microwave communication links the fading due to rain occurs. The methods to solve this problem include
62812. A microwave connector should have high SWR.
62813. Assertion (A): A small section of high impedance line is equivalent to a series inductance.Reason (R): A small section of a low impedance line is equivalent to a series resistance.
62814. Assertion (A): Bolometer is frequently used in microwave power measurement.Reason (R): In a bolometer the input microwave power causes a change in resistance.
62815. The radiation resistance of a doublet antenna of length dl is proportional to
62816. Which of the following statements is not correct regarding modes of electromagnetic energy transmission?
62817. Oscillations are obtained from a reflex klystron only for combinations of anode voltage and repeller voltage that give a favourable transit time.
62818. In the given figure shows a 10dB directional coupler. If power input at port 1 is 100 mW, power output at port 3 is
62819. The noise figure of klystron amplifier is about
62820. Which one of the following is true for EM wave propagation through rectangular waveguide of cross-section 2a x a
62821. In the given figure the line voltage after a number of reflections will be
62822. Which one of the following is also called 'rat race'?
62823. Radar principle is used in
62824. In an optional fiber the refractive index of cladding material should be
62825. In microwave circuits, a mode transducer is used to
62826. A waveguide connected to a circularly polarized antenna must be able to efficiently propagate both vertically and horizontally polarised waves.
62827. Which of the following is not used as a microwave mixer or detector?
62828. Integrated fin line can be utilized as a medium for constructing millimeter wave circuits.
62829. The secondary constants of a line are
62830. In a loss less line the propagation constant is equal to
62831. A rectangular wave guide has two stubs each of length connected at the source end. The stubs are circuited. Then the stubs present
62832. Slotted line can be used for measurement of high frequencies
62833. In a waveguide the dielectric region is generally
62834. In directional coupler of the given figure, the terms |S14| and |S23| of scattering matrix are nearly
62835. A line is excited by a 100 V, 200 ohm source and is terminated by 100 Ω resistance. If the voltage on line reaches steady value in 80 ns, the natural resonant frequency is
62836. A line of length slightly longer than and open circuited at far end behaves as
62837. The most commonly used magnetron is
62838. The effect of earth's magnetic field on radiowaves is minimum when
62839. A line of characteristic impedance Z0 branches into two line each with characteristic impedance Z0. The refracted voltage is
62840. The resistance values of a PIN diode under positive bias and negative bias respectively are about
62841. A PIN diode can be used
62842. What is the numerical aperture an optical fiber when critical angle is 30°?
62843. A line of length slightly less than and short circuited at far end behaves as
62844. In TE10 mode of rectangular waveguide
62845. Reflection from the object to be measured is significant only when the wavelength is
62846. The speed at which axial electric field due to signal advances in a TWT is equal to
62847. To ensure that only dominant TE10 mode propagates in a rectangular waveguide, the operating frequency
62848. In a microwave power measurement using bolometer, the principle of working is variation of
62849. Z0 = (Zoc Zsc)0.5
62850. A microwave junction is matched at all ports if the S matrix