CPW Fed Frequency Reconfigurable Antenna with Dual Band to Widband Capabilities for Millimeter Wave Applications

Abstract

This work presents a frequency-reconfigurable (FR) millimeter-wave (mm-wave) antenna employing a coplanar waveguide (CPW) feeding technique, capable of switching between dual-band and wideband operation. The antenna is fabricated on a Rogers RT/Duroid 5880 substrate and occupies an overall size of 1.31 λ0 × 0.93 λ0 × 0.075 λ0, where λ0 denotes the free-space wavelength at the center frequency. A PIN diode is integrated into the radiating structure to enable two distinct operating states- ON and OFF. In the OFF state, the antenna exhibits dual-band characteristics with impedance bandwidths of 26.6-30.1 GHz and 33.5-37.6 GHz (IBW = 12.35% and 11.53 %), resonating at 28 GHz and 36.25 GHz with corresponding peak gains of 4.9 dBi and 7.5 dBi. In the ON state, these two bands merge into a wideband response covering 24-38.2 GHz(IBW=45.66%), with resonances at 26.2 GHz, 34.6 GHz, and 36.5 GHz, achieving peak gains of 5.58 dBi, 5.3 dBi, and 7.6 dBi, respectively. The antenna performance is thoroughly evaluated using full-wave EM simulations, encompassing return loss (>10 dB), high gain, surface current distribution, broadside radiation patterns, and radiation efficiency (>95%). The results confirm stable radiation characteristics, enhanced bandwidth flexibility, and efficient frequency tunability, making the proposed design a strong candidate for integration into reconfigurable front-end modules for emerging mm-wave communication systems. © 2025 IEEE.