# US 2023/0275352 A1 · Liquid crystal-based microstrip patch antenna for widening frequency tuning range and miniaturizing radiating unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0275352 A1 - Document ID: US20230275352A1 - Status: Published application - Kind: A1 - Application number: 17/973,405 - Filed: 2022-10-25 - Published: 2023-08-31 - Earliest claimed: 2022-02-28 - Assignees: Korea Advanced Institute of Science and Technology - Applicants: Korea Advanced Institute of Science and Technology - Inventors: Seong Ook PARK; Jinki PARK; Ye-Eun CHI - Web page: https://patentgrep.com/patent/US20230275352A1 ## CPC - H01Q 9/0442: {with particular tuning means} - H01Q 9/045: {with particular feeding means (for circular polarisation H01Q9/0428)} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract A liquid crystal-based microstrip patch antenna for widening a frequency tuning range and miniaturizing a radiating unit are provided. The microstrip patch antenna includes at least one feeding unit, at least one radiating unit, a plurality of dielectric substrates including the feeding unit and the radiating unit and formed in a stack structure, a liquid crystal cavity interposed between the plurality of dielectric substrates stacked on each other, and at least one DC bias line to receive power from a power supply and to apply an electric field to the liquid crystal cavity through the radiating unit. ## Claims ### Claim 1 A microstrip patch antenna based on liquid crystal, comprising: at least one feeding unit; at least one radiating unit; a plurality of dielectric substrates including the at least one feeding unit and the at least radiating unit and formed in a stack structure; a liquid crystal cavity interposed between the plurality of dielectric substrates stacked on each other; and at least one direct constant (DC) bias line configured to receive power from a power supply and to apply an electric field to the liquid crystal cavity through the at least one radiating unit. ### Claim 2 (depends on 1) The microstrip patch antenna of claim 1, wherein the feeding unit has a feeding structure to transmit or receive a broadband frequency signal, as a resonance frequency of the antenna varies. ### Claim 3 (depends on 1) The microstrip patch antenna of claim 1, wherein the feeding unit includes: an aperture coupling slot having a form of an H-slot to feed a broadband frequency. ### Claim 4 (depends on 1) The microstrip patch antenna of claim 1, wherein the radiating unit includes: a Meander line slot including a conductive metal patch to widen a tuning range of an operating frequency of the antenna and to miniaturize the antenna. ### Claim 5 (depends on 1) The micro strip patch antenna of claim 1, wherein the radiating unit includes: a first radiating unit disposed under the liquid crystal cavity and provided in a patch type; and a second radiating unit disposed above the liquid crystal cavity provided in a patch type, and wherein a potential difference between the first radiating unit and the second radiating unit changes an intensity of the electric field applied to the liquid crystal cavity, such that a dielectric characteristic of the liquid crystal varies. ### Claim 6 (depends on 1) The microstrip patch antenna of claim 1, wherein the liquid crystal cavity is interposed between the plurality of dielectric substrates in which the radiating unit and the ground surface are positioned, and has a structure filled with the liquid crystal without leakage of the liquid crystal, as the liquid crystal is injected into the liquid crystal cavity. ### Claim 7 (depends on 1) The microstrip patch antenna of claim 1, wherein the liquid crystal cavity is interposed between the plurality of radiating units, and determined to be larger than patches of the plurality of radiating units, based on a fringe field of a resonance region. ### Claim 8 (depends on 1) The microstrip patch antenna of claim 1, wherein the DC bias line is disposed in the radiating unit, and is to supply power from an external power supply of the antenna to have a potential difference from the ground surface, such that a phase of the liquid crystal cavity is changed by inducing a change in a dielectric characteristic of the liquid crystal. ### Claim 9 (depends on 5) The microstrip patch antenna of claim 5, wherein the DC bias line includes: a first DC bias line to receive the power from the power supply to apply a voltage to the first radiating unit; and a second DC bias line to receive the power from the power supply to apply a voltage to the second radiating unit. ### Claim 10 A microstrip patch antenna based on liquid crystal, comprising: a first substrate including a second radiating unit provided in a patch type, and a second bias line to receive power from a power supply such that a voltage is applied to the second radiating unit; a second substrate disposed under the first substrate, and including a liquid crystal cavity for injecting liquid crystal; a third substrate disposed under the second substrate, and including a first radiating unit provided in the patch type and a first DC bias line to receive the power from the power supply such that a voltage is applied to the first radiating unit; and a fourth substrate disposed under the third substrate, and including a feeding unit and the ground surface and having a feeding structure to transmit a signal from the feeding unit to the first radiating unit. ### Claim 11 (depends on 10) The microstrip patch antenna of claim 10, wherein the first substrate, the second substrate, the third substrate, and the fourth substrate are a plurality of dielectric substrates formed in a stack structure. ### Claim 12 (depends on 10) The microstrip patch antenna of claim 10, wherein the second radiating unit includes: a Meander line slot including a conductive metal patch to widen a tuning range of an operating frequency of the antenna and to miniaturize the antenna. ### Claim 13 (depends on 10) The microstrip patch antenna of claim 10, wherein the second DC bias line is connected to the second radiating unit to apply a voltage to make a potential difference with the first radiating unit of the third substrate. ### Claim 14 (depends on 10) The microstrip patch antenna of claim 10, wherein the liquid crystal cavity is interposed between a plurality of dielectric substrates including the first radiating unit and the second radiating unit, and has a structure filled with the liquid crystal without leakage of the liquid crystal, as the liquid crystal is injected into the liquid crystal cavity. ### Claim 15 (depends on 10) The microstrip patch antenna of claim 10, wherein the liquid crystal cavity is provided under the second radiating unit of the first substrate, and determined to be larger than a patch of the second radiating unit, based on a fringe field of a resonance region. ### Claim 16 (depends on 10) The microstrip patch antenna of claim 10, wherein a potential difference between the first substrate and the third substrate changes an intensity of an electric field applied to the liquid crystal cavity of the second substrate, such that a dielectric characteristic of the liquid crystal varies. ### Claim 17 (depends on 10) The microstrip patch antenna of claim 10, wherein the first DC bias line is disposed in the first radiating unit of the third substrate to supply power from an external power supply of the antenna to have a potential difference from the ground surface, such that a phase of the liquid crystal cavity is changed by inducing a change in a dielectric characteristic of the liquid crystal. ### Claim 18 (depends on 10) The microstrip patch antenna of claim 10, wherein the feeding unit has a feeding structure including an aperture coupling slot to transmit and receive a broadband frequency signal, as a resonance frequency of the antenna varies. ### Claim 19 (depends on 18) The microstrip patch antenna of claim 18, wherein the aperture coupling slot has a form of an H-slot to feed a broadband frequency. ### Claim 20 (depends on 10) The microstrip patch antenna of claim 10, wherein the fourth substrate includes: a transition structure between a coaxial line for power-feeding of a microstrip line and the microstrip line, and wherein a plurality of conductive vias are disposed in the transition structure.