Pin-fed notched circular patch

Image of the Pin-fed notched circular patch.

Microstrip or patch antennas are popular in the microwave frequency range because of their simplicity and compatibility with circuit board technology. Dual-fed patches may be used to produce circularly polarised radiation but this requires the use of a feed network to provide equal excitations and a 90° phase shift between the ports. The notched patch described here has the advantage of using a single coaxial feed, orientated at 45° to the position of the notches.