RESUMEN

Beam-switching is one of the paramount focuses of 28 GHz millimeter-wave 5G devices. In this paper, a one-dimensional (1D) pattern reconfigurable leaky-wave antenna (LWA) was investigated and developed for wireless terminals. In order to provide a cost-effective solution, a uniform half-width LWA was used. The 1D beam-switching LWA was designed using three feed points at three different positions; by selecting the feeds, the direction of the beam can be switched. The antenna can switch the beam in three different directions along the antenna axis, such as backward, broadside, and forward. The 1D beam-switching antenna was fabricated, and because of the wide beamwidth, the measured radiation patterns can fill 128∘ of space (3 dB coverage), from θ = -64∘ to +64∘ at ϕ = 0∘. Following this, two of these antennas were placed at right angles to each other to achieve two-directional (2D) beam switching. The 2D beam-switching antenna pair was also prototyped and tested after integrating them into the ground plane of a wireless device. The antenna is able to point the beam in five different directions; moreover, its beam covers 167∘ (θ = -89∘ to +78∘) at ϕ = 0∘, and 154∘ (θ = -72∘ to +82∘) at ϕ = 90∘.

RESUMEN

A fixed-frequency beam-scanning leaky-wave antenna (LWA) array with three switchable dual-polarized beams is proposed and experimentally demonstrated. The proposed LWA array consists of three groups of spoof surface plasmon polaritons (SPPs) LWAs with different modulation period lengths and a control circuit. Each group of SPPs LWAs can independently control the beam steering at a fixed frequency by loading varactor diodes. The proposed antenna can be configured in both multi-beam mode and single-beam mode, where the multi-beam mode with optional two or three dual-polarized beams. The beam width can be flexibly adjusted from narrow to wide by switching between multi-beam and single-beam states. The prototype of the proposed LWA array is fabricated and measured, and both simulation and experimental results show that the antenna can accomplish a fixed frequency beam scanning at an operating frequency of 3.3 to 3.8 GHz with a maximum scanning range of about 35° in multi-beam mode and about 55° in single-beam mode. It could be a promising candidate for application in the space-air-ground integrated network scenario in satellite communication and future 6G communication systems.

Asunto(s)

RESUMEN

Microwave radar sensors have been developed for non-contact monitoring of the health condition and location of targets, which will cause minimal discomfort and eliminate sanitation issues, especially in a pandemic situation. To this end, several radar sensor architectures and algorithms have been proposed to detect multiple targets at different locations. Traditionally, beamforming techniques incorporating phase shifters or mechanical rotors are utilized, which is relatively complex and costly. On the other hand, metamaterial (MTM) leaky wave antennas (LWAs) have a unique property of launching waves of different spectral components in different directions. This feature can be utilized to detect multiple targets at different locations to obtain their healthcare and location information accurately, without complex structure and high cost. To this end, this paper reviews the recent development of MTM LWA-based radar sensor architectures for vital sign detection and location tracking. The experimental results demonstrate the effectiveness of MTM vital sign radar compared with different radar sensor architectures.