Microwave M4S2

In general, the term waveguide refers to constructs that only support non-TEM mode propagation. Such constructs share an important trait: they are unable to support wave propagation below a certain frequency, termed the ___

are modes below the cutoff frequency. They cannot propagate down the waveguide for any distance, dying away exponentially.

Because of the line-of-sight transmission of microwave signals, highly directive antennas are preferred because they do not waste the radiated energy and because they provide an increase in gain, which helps offset noise at microwave frequencies.

At low microwave frequencies, less than 4 GHz, standard antennas are commonly used, including the dipole and its variations.

is a fat, wide-bandwidth, half-wave dipole fed with low-loss coaxial cable.

The overall gain of a corner reflector antenna is _ to _ dB.

Microwave antennas must be some extension of or compatible with a waveguide.

Waveguide are not good radiators because they provide a poor impedance match with free space. This results in standing waves and reflected power.

This mismatch can be offset by flaring the end of the waveguide to create a