The VSWR can have any value between

The phase velocity for the $$T{E_{10}}$$ mode in an air-filled rectangular waveguide is

A person with a receiver is 5 Km away from the transmitter. What is the distance that this person must move further to detect a 3-dB decrease in signal strength?

Distilled water at $${25^ \circ }C$$ is characterized by $$\sigma = 1.7 \times {10^{ - 4}}$$ mho/m and $$ \in = 78{ \in _0}$$ at a frequency of $$3 GHz$$. Its loss tangent $$\tan \delta $$ is