Computer simulations of a four-element array antenna using polyethylene (PE) substrate and parameter analysis for compact, flexible wireless applications

Abstract

Flexible wireless applications in the C band microwave region require a conformal wideband antenna that resonates equally in all directions. In this paper, a polymer substrate-based array antenna is designed at an operating frequency of 7.3 GHz covering a bandwidth from 5 to 8 GHz. Conventional substrates such as FR4 (flame-retardant) have certain operational constraints with regard to high power, gain, and high dielectric constant (4.4), which results in a narrow impedance bandwidth and high return loss. In order to reduce this, a thermally stable and low-dielectric-constant (2.25) polyethylene (PE) substrate-based antenna is designed with a four-element array. The designed antenna is simulated, and its results are analysed and compared for both substrates. The gain and directivity increased to 6.25 and 6.45 dB, respectively. The return loss and voltage standing wave ratio (VSWR) reduced to −32.57 dB and 0.33. The radiation efficiency for the proposed four-element array antenna with polyethylene substrate was 96.8%. Thus, the resultant gain and efficiency of the polymer substrate antenna are improved compared with conventional antennas. The fabricated four-element array antenna with PE substrate provides a −22.25-dB return loss and standing wave ratio less than 2 through real-time testing at 7.3 GHz.