Design approach of a wideband frequency tunable triangular patch array with concurrent polarization alteration

摘要

A wideband frequency tunable triangular patch array with simultaneous polarization reconfiguring ability is designed and its performance is analysed. The antenna constitutes of three probe fed equilateral triangular patches on which narrow annular channels are created to place six varactors for continuous tuning purpose. All the triangular patches operate in dominant TMoi mode and provide circularly polarized radiation when fed with equal amplitude and 120° sequential phase difference. The resonant frequency of the antenna can be varied from 1.93 GHz to 2.52 GHz by varing the capacitance of six varactors from 4.27 pF to 1.15 pF, operating in reverse bias mode. The antenna shows overall tuning range of 27%. Along with frequency agility the antenna array can also be operated in both circularly polarized mode (RHCP and LHCP) at all operating frequencies. To achieve polarization reconfigurability at different frequencies a wideband tri phase shift feed network (TFN) providing equal amplitude and 0°, 120°, 240° phase difference is also designed. The antenna possesses stable radiation pattern and wide beam-width axial ratio at all operational bands.