Dual-Band Single/Dual-Beam High-Gain Patch Antenna Working in $TM_{20}$ and $TM_{21}$ Modes

A dual-band antenna with single/dual-beam radiation pattern is proposed. By harnessing the TM20 and TM21 modes, the antenna achieves dual-band functionality, positioning it as a promising candidate for future multiband communication systems. Feeding along the diagonal of the square patch antenna enables the integration of orthogonal modes. The TM21 and TM12 hybrid mode (HTM21) leads to split beams because of the intrinsic out-of-phase currents on the antenna aperture. To address this, a unique cut is introduced on the radiating patch surface to ensure a uniform current flow, resulting in a single, high-gain beam at broadside. In the TM20 and TM02 hybrid mode (HTM20), the two pairs of out-of-phase currents are reshaped into a single pair, generating a dual-beam radiation pattern. The proposed patch antenna with reshaped geometry does not require a feeding network and achieves pattern diversity in a simple form.