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arXiv · 2603.07818

A Curved Monopole Antenna for HF Radar with Enhanced Gain and Bandwidth

Masoud Salmani Arani·Reza Shahidi·Lihong Zhang
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Abstract

This paper presents the design and simulation of a new curved monopole antenna optimized for skywave HF radar applications, with a systematic investigation of the effects of curvature and fixed-section length on antenna performance. The proposed design achieves improved impedance matching, broader bandwidth, and enhanced realized gain compared to a conventional quarter-wavelength monopole at 15 MHz. Parametric analysis shows that fully bending the monopole degrades performance, whereas introducing a straight section and carefully optimizing the curvature enables a 18.5% gain increase and a 400 kHz bandwidth expansion. The single-element design is further extended to a 12-element linear array with 0.45λ spacing (where λ is the wavelength), demonstrating stable embedded-element behavior and improved low-to- moderate elevation gain for skywave over-the-horizon radar operation. At θ = 30°, the proposed array achieves 14.04 dBi compared to 13.11 dBi for the reference array, corresponding to 24% gain enhancement, which is significant in high-power HF radar systems. These results confirm that the proposed curved monopole antenna provides a compact, broadband, and scalable solution for next-generation HF radar arrays.

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Masoud Salmani Arani, Reza Shahidi, Lihong Zhang. 2026-03-08. A Curved Monopole Antenna for HF Radar with Enhanced Gain and Bandwidth. https://arxiv.org/abs/2603.07818

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