Consider the following statements relating to the micro-strip lines
1. Modes in micro-strip lines are purely TEM
2. Micro-strip lines is also called open strip line
3. Radiation loss in micro-strip line can be reduced by using thin high dielectric materials
4. Conformal transformation technique is quite suitable for solving micro problems
Which of the statements given above are correct?

Coupling into and out of a traveling-wave tube can be accompanied by a

A. Waveguide match

B. Cavity match

C. Direct coax-helix match

D. All of the above

When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have

A. A long time constant

B. Low-pass filters

C. The shortest possible time

D. The restricted high-frequency response

The antenna separations (in meters) required for optimum operation of a space diversity system can be calculated from:
where R = effective earth radius (m) and L = path length (m)

A. $${\text{S}} = \frac{{2\lambda {\text{R}}}}{{\text{L}}}$$

B. $${\text{S}} = \frac{{3\lambda {\text{R}}}}{{\text{L}}}$$

C. $${\text{S}} = \frac{{\lambda {\text{R}}}}{{\text{L}}}$$

D. $${\text{S}} = \frac{{\text{L}}}{{\lambda {\text{R}}}}$$

The aquadag coating on the inside of PPI tube is used

A. To focus the beam of primary electrons

B. To shield the electron beam from unidirectional magnetic

C. As a second anode and to prevent the build-up of secondary field

D. All of these