Design and Simulation of a Dual-Fed Circularly Polarized 1×4 Microstrip Patch Array for n7 Band Applications

This paper presents the design and full-wave simulation of a single-port dual-fed circularly polarized 1×4 microstrip patch antenna array for operation in the n7 band (2.620–2.690 GHz). In contrast to a conventional single-fed linearly polarized patch array, the proposed structure integrates a single-port corporate feed network with dual-feed excitation at each patch element to realize circularly polarized radiation while preserving a planar and manufacturable topology. The array is implemented on Rogers RT/duroid 5880 substrate with a relative permittivity of 2.2, loss tangent of 0.0009, and thickness of 1.524 mm. A single input port is divided into four branches, and each patch is excited through two feed points with an approximate 90° phase difference to support circularly polarized radiation. Full-wave simulations are carried out in CST Studio Suite to evaluate the impedance response, polarization performance, realized gain, and radiation characteristics of the array. The proposed design provides an axial-ratio value of 0.857 dB at 2.655 GHz, satisfying the commonly accepted 3-dB circular-polarization criterion, and achieves a realized gain of 13.1 dBi at the same frequency. In addition, the simulated results indicate a 3-dB axial-ratio angular region from 60° to 113.4°. These results show that the proposed array provides both high gain and improved polarization performance around the center frequency of the n7 band, making it a suitable candidate for sub-6 GHz wireless applications.