Pattern and frequency reconfiguration of patch antenna using PIN diodes

Abstract

In this article, an antenna with two patch elements is pattern and frequency reconfigured. One feed line is used to excite the two patch elements placed at any angle with respect to each other. The maximum rotation of each patch antenna element incorporated is 45°. For the impedance matching with 50 Ω, both elements are fed from the corner. The radiating elements are fed simultaneously using one feed line with the help of PIN diodes. When patch 1 is excited by biasing PIN diode 1, a broad side radiation pattern in the yz plane of the patch 1 is observed. Therefore, for the rotation angle by 7.5° the pattern rotation is about 5° Similarly, biasing PIN diode 2, resulted excitation of Patch 2. It is observed that pattern reconfiguration of 30° can be achieved by biasing PIN diode 1, whereas, up to −30° pattern reconfiguration can be achieved by exciting PIN diode 2, without compromising on the gain of the radiating elements. On the other hand, to achieve the frequency reconfiguration, two small radiating patches are added at 0.7 mm gap with the large radiating elements. PIN diodes are used between the small and large radiating elements. When diodes on the antenna elements are biased, patches resonate at 2.43 GHz otherwise the resonance occurred at 3.3 GHz. For the comparison with simulation results, a prototype is fabricated on low loss 1.524 mm thick Rogers TMM4 laminate (ɛr = 4.5, tanδ = 0.002). In the fabricated prototype, both the radiating elements are rotated at maximum angle and results are compared. A good agreement at both frequencies and radiation pattern reconfiguration is observed. The gain is almost 5.5 dBi for the reconfigured patterns at 3.3 GHz and 4.9 dBi at 2.43 GHZ. The antenna has maximum dimension of 58 × 100 mm2.