A liquid crystal phase-shifting unit and its phase-controlled antenna

Abstract

The invention discloses a liquid crystal phase shift unit and a phased antenna composed of the same. The liquid crystal phase shift unit is characterized in that a sandwich layer is formed by an upper-layer dielectric substrate and a lower-layer dielectric substrate which are arranged in parallel, nematic liquid crystal is enclosed in the sandwich layer to form a liquid crystal layer, metal micro-strip structures are formed on the surface of the upper-layer dielectric substrate and the surface of the lower-layer dielectric substrate, bias voltage is applied by means of the metal micro-strip structures, bias field is formed in the liquid crystal layer to enable the arrangement direction of liquid crystal molecules in the liquid crystal layer to be changed, and then the dielectric constant of the liquid crystal layer is changed and the phase position of reflected waves is changed; in an array formed by the liquid crystal phase shift unit, needed phase distribution is realized by applying different voltages to different units, so that corresponding wave beam directions are obtained or wavefront beamforming is achieved. Phase shift characteristics are changed with an electrical control method, working at the frequency band of 100-1000 GHz can be achieved, machining is easy, miniaturization is achieved, and cost is low.

Description

technical field [0001] The invention belongs to the imaging and radar fields of terahertz electronics, and particularly relates to a liquid crystal reflection phase-shifting unit and a phase-controlled reflection array antenna composed thereof. Background technique [0002] Compared with traditional mechanical scanning antennas, phased array antennas have more rapid and accurate beam scanning capabilities. It can achieve farther target search and more stable and reliable performance. [0003] Microstrip reflective array antennas combine the advantages of traditional parabolic reflective antennas and microstrip array antennas. It has high radiation efficiency and wide beam scanning angle. The core of microstrip reflect array research lies in how to design the structure and size of each unit to achieve specific phase compensation for the incident wave, thereby forming a specific beam. The traditional microstrip reflect array antenna mainly has the following design methods, ...

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Problems solved by technology

Among them, the parasitic characteristics of varactor diodes in the high-frequency band are relatively serious, and can only be used in low-frequency bands; the phase shifting characteristics of ferrite phase shifters are easy to migrate with the external environment, and it is difficult to accurately control; MEMS phase shifters require precise processing However, the high phase shifter based on PIN diodes needs to occupy a large area, which will inevitably increase the distance between array elements and deteriorate the grating lobe index of the antenna.

Due to the constraints of high-frequency performance of the device (varactor diode), processing difficulty (MEMS), circuit area (PIN diode) and other factors, the operating frequency of the above reflective phased arrays is generally below the W-band, and it is difficult to be competent for more high frequency work

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