A design for frequency reconfigurable annular slot antennas with circular polarization (CP) is described.The slot antenna is excited with a shorted microstrip line through coupling, and one varactor diode placed on the slot is used to generate CP radiation. By controlling the dc bias of the varactor, the CP operating frequency of the slot antenna can be switched between two frequencies with a frequency ratio of about 1.6; moreover, the antenna operating at each CP frequency has a return loss of less than 10 dB and the broadside radiation with a peak gain of higher than 3 dB.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Atomic and Molecular Physics, and Optics
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering