Design of a Novel Dual-Frequency Microstrip Patch Antenna with Slant Linear Polarization and Wide Tunable Frequency Ratio Range

This research introduces a novel dual-frequency microstrip patch antenna (MPA) design that features orthogonal slant linear polarizations and a wide frequency ratio (FR) range. A truncated square patch is employed to realize dual-band operation under TM₁₀ and TM₀₁ modes. Both modes are excited along diagonals of the square MPA leading to orthogonal slant polarizations. A shorting pin is loaded underneath the radiator to suppress TM₂₀ mode at the intermediate frequency. Simulated single-feed excitation demonstrates an arbitrary FR between 1.04 and 2.5. In order to confirm the feasibility of the suggested approach, an example of the antenna prototype with an FR of 2 is implemented and tested. Experimental results demonstrate that the antenna successfully achieves dual-band operation with a gain of 4.8 dB and 7.8 dB at 2.7 and 5.4 GHz, respectively, using probe excitation. This approach yields a marginal gain reduction of 0.8 dB at lower frequency when compared to a conventional MPA resonating at the identical frequency. The level of cross-polarization is less than − 20 dB at two frequencies. The proposed antenna stands out for its lightweight and low-profile design, wide FR range, low cross-polarization, stable unidirectional radiation pattern, simple structure and ease of fabrication, making it an ideal choice for dual-band applications.