Software-Defined Radio with Integrated 4 × 4 Antenna Array for Wireless Communication

In this paper, wireless communication is demonstrated using a Software-Defined Radio (SDR) integrated with a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4\times 4$</tex> Microstrip Patch Antenna Array (MPAA) operating at 1.8 GHz. The antenna features an inset-fed configuration, achieved by replicating a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\times 4$</tex> array constructed with FR4 epoxy substrate, which has a dielectric constant of 4.4 and loss tangent of 0.02 in ANSYS HFSS. The fabricated <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4\times 4$</tex> antenna array exhibits a return loss of 30.5 dB and a gain of 11.2 dBi. The SDR is used to excite the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4\times 4$</tex> antenna array. The antenna is rotated to various angles to check the maximum scan capability. The study includes the analysis of two modulation schemes: Quadrature Phase Shift Keying (QPSK) and 16-Quadrature Amplitude Modulation (QAM). Performance observations are conducted for transmission distances of 5 meters and 10 meters. The results demonstrate the effectiveness of the antenna in practical wireless communication scenarios and provide insights into its performance across different angles and distances.