A Versatile Triangular Patch Array for Wideband Frequency Alteration With Concurrent Circular Polarization and Pattern Reconfigurability

This paper focuses on the design with experimental verification of a circular polarization (CP) and pattern reconfigurable triangular patch array simultaneously operating at various tunable frequencies. The resonant frequency of the antenna can be altered from 1.97 to 2.54 GHz (25.3% tunable bandwidth) by varying the capacitance values from 4.27 to 1.15 pF of the six varactors fixed between the annular slots on the three triangular patches. A wideband phase shifting network with switching capability is also designed which facilitates the antenna to operate it in both types of CP and pattern reconfigurable modes at each frequency. The antenna is tested in receiving mode and it shows a maximum realized gain of 3.1 dBc when operated in any of the CP mode and 1.45 dB for pattern reconfigurability mode. It has a very wideband axial ratio (AR) value (<3 dB) at each reconfigured frequency and also covers the entire frequency agility bandwidth. Investigation confirms that the antenna produces circularly polarized radiation pattern with minimum AR beamwidth of 24 degrees at all frequency bands for both types of CP radiation. It is also observed that the antenna pattern can be rotated at 120 degrees angle in the complete azimuth plane with a wide 3 dB beamwidth of +/- 45 degrees at its operating frequencies. The multifaceted reconfiguring ability of the antenna enables it to serve many futuristic communication system requirements such as supporting multiple radios and maintaining signal quality in diverse climatic conditions.