For an 8 feet (2.4 m) parabolic disk antenna operating at 4 GHz, the minimum distance required for far field measurement is closest to

The three regions shown in Fig. are all lossless and non-magnetic. Find

(a) Wave impedance in mediums 2 and 3.
(b) d such that medium 2 acts as a quarter wave $$(\lambda /40$$)transformer.
(c) Reflection coefficient $$(\Gamma )$$ and voltage standing wave ratio (VSWR) at the interface of the medium 1 and 2, when $$d = \lambda /4$$.

If the diameter of a $$\lambda /2$$ dipole antenna is increased from $$\lambda /100$$ to $$\lambda /50$$ then is

The eigen values of the matrix $$\left[ {\matrix{ 2 & { - 1} & 0 & 0 \cr 0 & 3 & 0 & 0 \cr 0 & 0 & { - 2} & 0 \cr 0 & 0 & { - 1} & 4 \cr } } \right]$$ are