A uniform plane wave in air impinges at 45° angle on a lossless dielectric material with dielectric constant $${\varepsilon _r}$$. The transmitted wave propagates in a 30° direction with respect to the normal. The value of $${\varepsilon _r}$$ is

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