Reconfigurable Liquid Crystal Dielectric Image Line Leaky Wave Antenna at W-Band

Abstract

This paper presents a reconfigurable dielectric image line leaky wave antenna at W-band. Reconfigurability is achieved by applying bias to anisotropic liquid crystal (LC) filled into the antenna. Instead of separating RF components and DC-bias network by complex or space consuming methods, the bias electrodes are simultaneously used as radiation elements. In order to evaluate this concept, a non-reconfigurable antenna with isolated unit cells is compared to a reconfigurable antenna, which has its unit cells connected by a metallic line. The non-reconfigurable demonstrator shows gain of up to 18 dBi and can scan through broadside from −30 • to +10 • in the investigated frequency range from 75 GHz to 102 GHz. This frequency scanning sector can be shifted by 10 • when utilizing the reconfigurable LC antenna, while gain of up to 15 dBi is maintained. Since the bias electrodes are directly mounted on the image line, less than 50 V is necessary to control the LC. The antenna is comparably easy to fabricate, and only one bias voltage is directly related to a steering angle, which can be advantageous compared to complex phased arrays with multiple LC phase shifters.INDEX TERMS Beam steering, dielectric image line, leaky wave antennas, liquid crystal, W-band.

Reconfigurable holographic leaky‐wave antenna based on liquid crystal materials

“…At the same time, it has the advantages of large scanning angle and strong beam symmetry comparing with the traditional holographic antenna. [3][4][5][6]8,13 Through simulation and test results, it is verified that the antenna has a large Angle scanning function, and the beam scanning range of −63°t o 63°is achieved at a single frequency point of 36 GHz.…”

“…4,5,13 They use their own structure to realize beam-scanning, so their frequency can be high, but the beam-scanning range is not large. There are also some literatures, such as Tesmer et al, 8 which make use of liquid crystal materials with frequencies even up to terahertz, which also verifies that liquid crystal materials have a bright future in the microwave and terahertz frequency bands.…”

“…Compared with the traditional reflective array antenna, 11,12 the feed form is more flexible, and the shielding of the feed can be avoided, greatly improving the monitoring range of the antenna system. At the same time, it has the advantages of large scanning angle and strong beam symmetry comparing with the traditional holographic antenna 3–6,8,13 . Through simulation and test results, it is verified that the antenna has a large Angle scanning function, and the beam scanning range of −63° to 63° is achieved at a single frequency point of 36 GHz.…”

“…The addition of ferrite material increases the weight and loss of the device. As a new type of electrically tunable material, liquid crystal material not only has continuous tunability of dielectric constant, but also has the characteristic of lower loss with higher frequency, 8 which can be used to improve the gain and integration of antenna system.…”

A Ka-band Holographic Metasurface Leaky-wave Antenna Based on Liquid Crystal

“…It achieves a beam scanning range of -45° to +51° at 35 GHz, with a maximum gain of 9.8 dB and a reflection coefficient below -10 dB. Henning Tessmer proposed a reconfigurable LC dielectric image line leaky-wave antenna with a high gain of 18 dBi, but a limited beam scanning range from -30° to +10° [35].…”