Compact 2-port linearly and circularly polarized antennas using low cross-polarization miniaturized patch

This paper presents compact two-port antenna arrays with linear and circular polarization based on a miniaturized patch radiator with extremely low cross-polarization radiation. The primary radiator employs a conventional rectangular patch loaded with multiple slots and meander-line structures to increase the equivalent capacitance, thereby lowering the resonant frequency without enlarging the antenna footprint. Owing to the inherently low cross-polarization radiation of the miniaturized radiator, two compact 2-port array configurations are implemented: the first provides polarization diversity under linear polarization, while the second employs a hybrid coupler to achieve dual circular polarization. Both arrays operate at 4.3 GHz and possess compact physical dimensions with stable radiation performance. Compared with state-of-the-art works, the proposed designs exhibit a significantly reduced size while maintaining competitive radiation characteristics, making them suitable for space-constrained wireless systems.