Triple Circular Radiators Frequency Diversity Microstrip Antenna with AMC Structure

In this study, a new design of a frequency-agile microstrip antenna consisting of three circular radiators of different sizes on the front side and triangular AMCs on the back of a FR4_epoxy substrate (33 × 30 × 1.6 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>) is presented. The antenna functions within various frequency ranges depending on the states of the diodes: 4.72 – 6.92 GHz with a gain of 4.53 dB and 2.51 – 2.84 GHz with a gain of 0.8 dB (both diodes ON); 7.35 – 7.8 GHz and 3.48 – 3.7 GHz with gains of 4.59 dB and 1.61 dB, respectively (D2 ON); 3.38 – 3.58 GHz, 4.80 – 4.94 GHz, and 7.43 – 7.8 GHz with gains of 2.42 dB, 1.85 dB, and 3.64 dB, respectively (both diodes OFF); and 4.71 – 4.85 GHz with a gain of 0.6 dB for the state of D1 ON. An optimizing mechanism using a PIN diode with regard to the feed line and ground plane was designed for stability and reconfigurability. These characteristics make this antenna suitable for 5G communication, IoT, and Radar applications. The simulation results validate the design performance as it operates efficiently with radiation patterns that are stable throughout its states.