CN-117317543-B - Small terahertz MEMS single-pole four-throw switch based on shared composite beam

CN117317543BCN 117317543 BCN117317543 BCN 117317543BCN-117317543-B

Abstract

The invention discloses a small terahertz MEMS single-pole four-throw switch based on a shared composite beam, and belongs to the technical field of radio frequency MEMS. The single-pole four-throw switch based on the integral beam consists of a microstrip main feeder, a bifurcation transition structure, a low-loss switch structure and a microstrip output line. The MEMS switch is formed by a metal-medium integral composite beam to form a high-isolation symmetrical structure, the crane-shaped arm and the shared folding arm are combined to enable the switch to have minimized size and low pull-down voltage, the corresponding part of the beam is pulled down by electrostatic force adsorption generated by potential difference between the bottom electrode and the metal part of the shared beam, the metal contact on the beam enables the corresponding microstrip output line to be conducted, and when one of the MEMS switch lines is conducted and the other MEMS switch lines are disconnected, signal transmission is completed. The reconfigurable switch is formed by symmetrically and compactly arranging four asymmetric single-pole single-throw switch units, has high isolation in an ultra-wide band, has a path reflection coefficient smaller than-15 dB in a DC-350GHz frequency band, has in-band insertion loss smaller than 1.8dB, and has isolation larger than 15dB.

Inventors

YANG GUANGYAO
ZHANG NAIBAI
SONG RUILIANG
LIU NING
DENG KUN

Assignees

中国电子科技集团公司第五十四研究所

Dates

Publication Date: 20260512
Application Date: 20231012

Claims (5)

1. The miniature terahertz MEMS single-pole four-throw switch based on the shared composite beam is characterized by comprising a microstrip primary feeder (1), a trapezoid protruding bifurcation structure (2), a voltage bias line group, a special-shaped MEMS switch and microstrip secondary feeders (20, 21, 22 and 23); the trapezoid protruding bifurcation structure (2) consists of a T-shaped junction power divider and two trapezium pieces, wherein the two trapezium pieces are in one-to-one correspondence with the two tail ends of the T-shaped junction power divider, the lower bottom edges of the trapezium pieces are clung to one side of the tail end of the T-shaped junction power divider, and the two trapezium pieces are respectively positioned at the two output ends of the T-shaped junction power divider in the same orientation; The tail end of the T-shaped junction power divider and the upper bottom edge of the trapezoid piece are connected with the microstrip secondary feeder one by one through special-shaped MEMS switches, and the special-shaped MEMS switches are in one-to-one correspondence with the microstrip secondary feeder; The four special-shaped MEMS switches share the same elastic dielectric film bridge (7), and a metal bridge-shaped passage and a pull-down metal beam on each special-shaped MEMS switch are positioned on the lower surface of the elastic dielectric film bridge, and are supported and suspended through corresponding metal bridge piers, and pull-down electrodes are arranged below the pull-down metal beams; The metal bridge-shaped passage and the pull-down metal beam on the same special-shaped MEMS switch are adjacent and have no contact, The two special-shaped MEMS switches corresponding to the upper bottom edge of the trapezoid piece share a pull-down metal bridge, and the shared pull-down metal bridge is of a Chinese character 'ri' -shaped structure; the pull-down metal bridges of the two special-shaped MEMS switches corresponding to the output ends of the T-shaped junction power divider are of a square-shaped structure.
2. The small terahertz MEMS single-pole four-throw switch based on a shared composite beam according to claim 1, wherein an initial section of a microstrip secondary feeder connected by a trapezoid is parallel to a microstrip primary feeder, and the microstrip secondary feeder connected to the end of a T-junction power divider is perpendicular to the microstrip primary feeder; wherein, two microstrip second grade feeder that are connected through trapezoidal piece are all buckled 135, and deviate from the setting.
3. The shared composite beam-based small terahertz MEMS single-pole, four-throw switch of claim 1, wherein the portion of the elastic dielectric film bridge above the metal bridge-like via is perpendicular to the long side of the metal bridge-like via.
4. The small terahertz MEMS single-pole four-throw switch based on the shared composite beam according to claim 1 is characterized in that a high-frequency low-loss dielectric material is used as a substrate, a corrosion-resistant low-resistivity metal material is used as a metal beam, a compound dielectric material with a low elastic coefficient is used as a dielectric film bridge, the metal beam is manufactured through a sacrificial layer technology, and the dielectric film bridge is tightly adhered to the metal beam, so that the dielectric film bridge can be driven by the downward pulling force of the metal beam.
5. The small terahertz MEMS single-pole four-throw switch based on a common composite beam according to claim 1, wherein the microstrip primary feed line, microstrip secondary feed line, and voltage bias line groups together form a delta configuration.

Description

Small terahertz MEMS single-pole four-throw switch based on shared composite beam Technical Field The invention relates to a miniaturized terahertz MEMS single-pole four-throw switch based on a shared composite beam, which is mainly applied to a radio frequency system of a terahertz frequency band and belongs to the technical field of radio frequency MEMS. Background The radio frequency switch based on the MEMS micro-electromechanical structure has wide and important application requirements in satellite communication front ends, broadband network systems and radar systems covering microwave frequency bands due to the advantages of wide working bandwidth, high isolation, small insertion loss and the like. Worldwide, many researches on low-frequency microwave band MEMS switches are mainly divided into cantilever beam switches and clamped beam switches, high-power switches and low-power switches, single-pole single-throw switches and single-pole multi-throw switches and the like. The single-pole multi-throw switch can complete switching of radio frequency signal paths under the condition that the number of the switch beams is minimum, provides new dimensions for simplifying control circuit design, and achieves miniaturization of the switching paths, but the MEMS single-pole multi-throw switch has the defects of low high-frequency cut-off frequency, difficult miniaturization and large influence on mechanical structure stability. The research results of the terahertz frequency band MEMS switch are few, the single-pole multi-throw MEMS switch of the terahertz frequency band is not yet researched and published, the overall design difficulty of the radio frequency performance and the mechanical structure is high, the existing high-frequency MEMS switch often needs a large beam size to have ideal radio frequency performance, the structure is often simple, and the high-frequency trafficability is not ideal. Cantilever-based direct contact single pole, four throw MEMS switches, such as those developed by n.scott Barker et al 2011, university of virginia, usa, can be covered to 75GHz and switching line-based high frequency phase shifters have been developed based on this switch, but the return loss of the switch is only 13dB at 75 GHz. Then Selin Tolunay Wipf in IEEE Microwave AND WIRELESS Components Letters published a paper for a D-band single pole double throw MEMS switch made using SiGe BiCMOS technology that can achieve an insertion loss of 1.42dB and an isolation of 54.5dB at 140GHz, but the isolation will deteriorate to 18.25dB at 170GHz, with an increase in insertion loss. In 2022, the N.Scott Barker et al designs a terahertz cantilever beam switch based on a coplanar waveguide by utilizing silicon and fused quartz, but a MEMS single-pole multi-throw switch working at high frequency terahertz is not really realized. The current terahertz MEMS switch has the defects of larger structural size, poor high-frequency isolation and large loss, and the current terahertz MEMS switch is difficult to meet the requirements of application on radio frequency devices such as antennas. However, MEMS switches in the terahertz frequency band have not been studied at present in connection with single-pole, multi-throw miniaturization. Disclosure of Invention In order to solve the problems in the background technology, the design of the invention is a small terahertz MEMS single-pole four-throw switch based on a shared composite beam, and can meet the requirement of terahertz frequency band radio frequency path switching. The designed switch has the characteristics of miniaturization, high cut-off frequency, low insertion loss, high isolation and the like. In order to solve the technical problems, the invention is realized by the following technical scheme: The miniaturized terahertz MEMS single-pole four-throw switch based on the shared composite clamped beam comprises a microstrip primary feeder 1, a trapezoid protruding bifurcation structure 2, a voltage bias line group, a special-shaped MEMS switch and microstrip secondary feeders 20, 21, 22 and 23; The trapezoid protruding bifurcation structure 2 mainly comprises a T-shaped junction power divider and two trapezium pieces, wherein the two trapezium pieces are in one-to-one correspondence with the two tail ends of the T-shaped junction power divider; The tail end of the T-shaped junction power divider and the upper bottom edge of the trapezoid piece are connected with the microstrip secondary feeder one by one through special-shaped MEMS switches, and the special-shaped MEMS switches are in one-to-one correspondence with the microstrip secondary feeder; The four special-shaped MEMS switches share the same elastic dielectric film bridge 7, and a metal bridge-shaped passage and a pull-down metal beam on each special-shaped MEMS switch are positioned on the lower surface of the elastic dielectric film bridge, and are supported and suspended by corresponding metal bridge piers, an