Sheng Li

This paper presents a novel dual-polarized leaky-wave antenna (LWA) that integrates dual-channel operation, polarization reconfigurability, and electronically controlled beam scanning into a simple structure. The architecture consists of a radiating superstrate, a 90° hybrid coupler, and gap waveguides (GWs). Two rows of patch elements on the superstrate are excited through orthogonal slots etched on a shared ground. PIN diodes and their electronically controlled network are placed beneath the slots to tune the radiation state of each element. The 90° hybrid coupler, implemented via a metal pin array, is integrated into the GWs to form the feed structure. A binary hologram control method based on the holographic principle is proposed, allowing real-time switching of polarization states and beam directions through the manipulation of PIN diodes. As a result, the antenna supports simultaneous dual-channel operation with four pairs of reconfigurable orthogonal polarizations—right-hand/left-hand circular polarization (RHCP/LHCP), LHCP/RHCP, horizontal/vertical polarization (HP/VP), and VP/HP—with independent beam scanning over a 100° range in each polarization state. A prototype is fabricated and measured, validating polarization switching among all four states and beam scanning from –50° to 50°. Owing to its dual-channel operation, polarization reconfigurability, and beam-scanning capability, the proposed antenna is a promising candidate for millimeter-wave applications.

A novel microstrip magnetic-current electronically steerable leaky-wave antenna (LWA) is proposed, capable of wide-angle two-dimensional (2-D) beam scanning over a broad band. The radiation mechanism is realized through a simple microstrip magnetic-current array. To enable dynamic beam control, each magnetic-current controlling unit is integrated with a PIN diode to allow operating state switching. Holographic method is employed to achieve real-time 2-D beam scanning in both azimuth and elevation planes. Besides, conventional LWAs often suffer from beam squint, which degrades the stability of signal strength in specific directions in the bandwidth. To address this issue, a center-fed substrate integrated waveguide is developed for the excitation of the microstrip magnetic-current array. This architecture effectively suppresses beam squint and stabilizes the gain across the signal bandwidth. A prototype is fabricated and measured, demonstrating 2-D beam scanning from 4.5 to 5.6 GHz. The antenna achieves a peak realized gain of 15.66dBi at 5.0 GHz. Measured gain drops are constrained to 3.90dB for scans up to ±50° and 5.18dB up to ±60°, with an average reduction of 3.75dB toward the band edges. Measured results show a good agreement with the simulated ones, validating the effectiveness of the proposed design. Due to its simple structure, low profile, low cost and lightweight, the antenna is suited for beam-scanning communication scenarios.

In this letter, a hexa-polarization reconfigurable fixed-frequency beam scanning leaky-wave antenna (LWA) operating in the millimeter-wave band is developed. Two parallel gap waveguides (GWs) are used as the basic transmission structure, and wide serrated ridges are adopted to produce quasi-TEM mode and slow-wave transmission in the GWs. A square patch array excited by the GWs is designed to generate radiation with desired polarization. A control structure loaded with PIN diode is applied to tune the working state of each patch unit. Then based on the holographic theory, the hologram on the antenna aperture can be manipulated by controlling the states of all the patch elements. In this way, six polarizations can be obtained (±45° linear polarizations, horizontal polarization, vertical polarization, left-hand circular polarization and right-hand circular polarization), and independent fixed-frequency beam scanning for each polarization can be achieved. In the measurement, a beam-scanning range of 100° is realized for each polarization state, and the property of two circular polarizations is also verified by the measured axial ratios. Therefore, this LWA shows potential in the millimeter-wave applications that demand polarization agility and fixed-frequency beam scanning.