Design of a DGS Based Frequency Reconfigurable Microstrip Patch Antenna Integrated with PIN

A slotted Defected Ground Structure (DGS) based frequency reconfigurable microstrip patch antenna is proposed and designed for different switchable frequencies. This frequency diversified antenna is applicable for more than one microwave wireless applications. DGS structure enhances the antenna efficiency and performance. In order to make antenna reconfigurable, 2 PIN Diodes are integrated on the main antenna patch. Biasing of such PIN diodes makes the antenna switchable for different modes. The proposed antenna has a compact size with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20 \times 20 \text{mm}^{2}$</tex> patch. Due to ease of availability of Flame Retardant (FR4), it is used as a dielectric substrate with relative permittivity 4.4 and dissipation loss equal to 0.10. The proposed DGS based geometry operates in three different modes for different biasing conditions, achieving distinct resonant frequencies: Mode 1 at 3.4 GHz (D2 ON, D1 OFF) with a reflection coefficient (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S}_{11}$</tex>) of -12.92 dB, Mode 2 at 5.5 GHz (D1 ON, D2 OFF) with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S}_{11}$</tex> of -27.54 dB, and Mode 3 at 4.5 GHz (D1 ON, D2 ON) with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{S}_{11}$</tex> of -38.57 dB. This design is unique and novel as this antenna uses only 2 PIN diodes for achieving three different operating frequency with very good return loss value and applicable for modern day communication systems, including IoT, 5G, and defense applications. Ansys HFSS 15 antenna software is used for designing and analyzing the simulated results.