A broadband RF MEMS single-pole ten-throw switch for L~U band

Abstract

The present invention belongs to the field of RF MEMS technology, and specifically relates to a broadband RF MEMS single-pole ten-throw switch in the L~U band, wherein the input signal line and ten output signal lines are all arranged on a dielectric substrate, and a disk power divider is provided at the end of the input signal line to ensure that the length from the input port to each output port is substantially equal and the RF performance is similar. The compact design of the present invention not only has the advantages of small size and high integration, but also can save the use of a single switch device while providing ten channel selections. In addition, the present invention obtains low driving voltage and high isolation by optimizing the upper electrode of the MEMS switch, and has high isolation and good insertion loss performance in the working range of 1~60GHz.

Description

Technical Field

[0001] The invention belongs to the technical field of RF MEMS, and in particular relates to a broadband RF MEMS single-pole ten-throw switch in the L-U band. Background Art

[0002] RF MEMS switches have been a research hotspot in the MEMS field since the 1990s. As a basic device in microwave circuits, RF MEMS switches are used to control the on and off of microwave signals in transmission systems. Since the single-pole multi-throw switch designed using RF MEMS technology shows excellent RF performance, it has gradually become an ideal choice for realizing multi-channel and adjustable functions of RF devices (such as filters, delay devices, and resonators).

[0003] At present, SPMT switches have the problems of low working frequency, narrow frequency band and few ports. Most SPMT switches (8 or more) are designed with PIN tubes, such as the SP8T switch designed by the Shanghai Advanced Research Institute of the Chinese Academy of Sciences, which has an insertion loss of ≤1dB and isolation of ≥35dB for each channel in the 0~2.4 GHz frequency band. Its disadvantages are narrow frequency band, difficult to control port consistency, and high process difficulty, which makes it difficult to meet the needs of future products. Summary of the invention

[0004] In view of the technical problems that the above-mentioned SPMT has narrow frequency band, difficult to control port consistency, high process difficulty and is difficult to meet the needs of future products, the present invention provides a broadband RF MEMS single-pole ten-throw switch in the L~U band, which has the characteristics of large number of ports, high integration, high isolation, low driving voltage and wide operating range.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A broadband RF MEMS single-pole ten-throw switch in the L~U band comprises a dielectric substrate, an input signal line, a first output signal line, a second output signal line, a third output signal line, a fourth signal output line, a fifth signal output line, a sixth signal output line, a seventh signal output line, an eighth signal output line, a ninth signal output line, and a tenth signal output line. The input signal line is arranged on the dielectric substrate, and a disc power divider is arranged at the end of the input signal line. A first branch, a second branch, a third branch, a fourth branch, a fifth branch, a sixth branch, a seventh branch, an eighth branch, a ninth branch, and a tenth branch are sequentially arranged around the disc power divider. The first branch is connected to the first output signal line, the second branch is connected to the second output signal line, the third branch is connected to the third output signal line, the fourth branch is connected to the fourth signal output line, the fifth branch is connected to the fifth signal output line, the sixth branch is connected to the sixth signal output line, the seventh branch is connected to the seventh signal output line, the eighth branch is connected to the eighth signal output line, the ninth branch is connected to the ninth signal output line, and the tenth branch is connected to the tenth signal output line.

[0007] A first ground wire and a second ground wire are equidistantly arranged on both sides of the input signal line, a second ground wire and a third ground wire are equidistantly arranged on both sides of the first output signal line, a third ground wire and a fourth ground wire are equidistantly arranged on both sides of the second output signal line, a fourth ground wire and a fifth ground wire are equidistantly arranged on both sides of the third output signal line, a fifth ground wire and a sixth ground wire are equidistantly arranged on both sides of the fourth signal output line, a sixth ground wire and a seventh ground wire are equidistantly arranged on both sides of the fifth signal output line, a seventh ground wire and an eighth ground wire are equidistantly arranged on both sides of the sixth signal output line, an eighth ground wire and a ninth ground wire are equidistantly arranged on both sides of the seventh signal output line, a ninth ground wire and a tenth ground wire are equidistantly arranged on both sides of the eighth signal output line, a tenth ground wire and an eleventh ground wire are equidistantly arranged on both sides of the ninth signal output line, and the eleventh ground wire and the first ground wire are equidistantly arranged on both sides of the tenth signal output line.

[0008] The first output signal line, the second output signal line, the third output signal line, the fourth signal output line, the fifth signal output line, the sixth signal output line, the seventh signal output line, the eighth signal output line, the ninth signal output line and the tenth signal output line are all provided with MEMS switch anchor points, and the first branch, the second branch, the third branch, the fourth branch, the fifth branch, the sixth branch, the seventh branch, the eighth branch, the ninth branch and the tenth branch are all provided with MEMS switch contacts, the MEMS switch anchor point is fixedly connected to one end of the MEMS switch upper electrode, and the other end of the MEMS switch upper electrode is arranged directly above the MEMS switch contact.

[0009] The upper electrode of the MEMS switch is a triangular structure, and a plurality of openings are formed on the upper electrode of the MEMS switch.

[0010] A driving electrode is led out from below the upper electrode of the MEMS switch.

[0011] Air bridge anchor points are arranged above the first ground wire, the second ground wire, the third ground wire, the fourth ground wire, the fifth ground wire, the sixth ground wire, the seventh ground wire, the eighth ground wire, the ninth ground wire, the tenth ground wire and the eleventh ground wire, and the air bridge anchor points are connected by air bridges.

[0012] The dielectric substrate is made of glass, ceramic or high-resistance silicon.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The compact design of the present invention not only has the advantages of small size and high integration, but also can save the use of a single switch device while providing ten channel options. In addition, the present invention obtains a low driving voltage by optimizing the upper electrode of the MEMS switch, and has high isolation and good insertion loss performance in the working range of 1~60GHz. The present invention adopts a coplanar waveguide transmission structure to facilitate characteristic impedance matching. Its shape is simple and regular, avoiding the punching process, and is easy to implement in process processing. It is suitable for mass production, thereby improving the yield rate of the switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0016] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0017] Figure 1 This is an overall schematic diagram of the RF MEMS single-pole ten-throw switch of the present invention;

[0018] Figure 2 A top view of the RF MEMS single-pole ten-throw switch of the present invention;

[0019] Figure 3 This is a schematic diagram of a MEMS switch of the present invention;

[0020] Figure 4 Schematic diagram of a disk power divider in the RF MEMS single-pole ten-throw switch of the present invention;

[0021] Figure 5 Schematic diagram of the air bridge in the RF MEMS single-pole ten-throw switch of the present invention;

[0022] Figure 6 It is a simulation diagram of the insertion loss of the conducting channel and the isolation of the remaining channels of the present invention.

[0023] Wherein: 1 is a dielectric substrate, 2 is an input signal line, 3 is a first ground line, 4 is a second ground line, 5 is a first output signal line, 6 is a third ground line, 7 is a second output signal line, 8 is a fourth ground line, 9 is a third output signal line, 10 is a fifth ground line, 11 is a fourth output signal line, 12 is a sixth ground line, 13 is a fifth output signal line, 14 is a seventh ground line, 15 is a sixth output signal line, 16 is an eighth ground line, 17 is a seventh output signal line, 18 is a ninth ground line, 19 is an eighth output signal line, 20 is a tenth ground line, 21 is a ninth output signal line, 22 is the eleventh ground wire, 23 is the tenth output signal wire, 24 is the upper electrode of the MEMS switch, 25 is the air bridge, 26 is the disc power divider, 201 is the MEMS switch anchor point, 202 is the opening, 203 is the MEMS switch contact, 204 is the driving electrode, 401 is the first branch, 402 is the second branch, 403 is the third branch, 404 is the fourth branch, 405 is the fifth branch, 406 is the sixth branch, 407 is the seventh branch, 408 is the eighth branch, 409 is the ninth branch, 410 is the tenth branch, and 301 is the air bridge anchor point. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. These descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0025] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0027] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] In this embodiment, if Figure 1 As shown, a disk power divider 26 is provided at the end of the input signal line 2. The disk power divider 26 is provided with a first branch 401, a second branch 402, a third branch 403, a fourth branch 404, a fifth branch 405, a sixth branch 406, a seventh branch 407, an eighth branch 408, a ninth branch 409, and a tenth branch 410 in sequence. A MEMS switch contact 203 is provided above the first branch 401 to the tenth branch 410. One end of the switch upper electrode 24 is fixedly connected to each output signal line by a MEMS switch anchor 201, and the other end is suspended above the MEMS switch contact 203. A driving electrode 204 is provided below the MEMS switch upper electrode 24. Air bridge anchors 301 are provided above the first ground line 3 to the eleventh ground line 22, and an air bridge 25 is provided above the first ground line 3 to the eleventh ground line 22 through the fixed anchor 301.

[0029] Further, if Figure 2As shown, the first ground line 3 and the second ground line 4 are equidistantly arranged on both sides of the input signal line 2, the second ground line 4 and the third ground line 6 are equidistantly arranged on both sides of the first output signal line 5, the third ground line 6 and the fourth ground line 8 are equidistantly arranged on both sides of the second output signal line 7, the fourth ground line 8 and the fifth ground line 10 are equidistantly arranged on both sides of the third output signal line 9, the fifth ground line 10 and the sixth ground line 12 are equidistantly arranged on both sides of the fourth signal output line 11, and the sixth ground line 13 is equidistantly arranged on both sides of the fifth signal output line 13. 12 and the seventh ground line 14, the seventh ground line 14 and the eighth ground line 16 are equidistantly arranged on both sides of the sixth signal output line 15, the eighth ground line 16 and the ninth ground line 18 are equidistantly arranged on both sides of the seventh signal output line 17, the ninth ground line 18 and the tenth ground line 20 are equidistantly arranged on both sides of the eighth signal output line 19, the tenth ground line 20 and the eleventh ground line 22 are equidistantly arranged on both sides of the ninth signal output line 21, and the eleventh ground line 22 and the first ground line 3 are equidistantly arranged on both sides of the tenth signal output line 23. The transmission structure formed by the signal line and the ground lines on both sides is an ordinary coplanar waveguide line, in which the signal line and the ground lines on both sides are equidistant, and the spacing affects the output and input impedance of the single-pole ten-throw switch. The transmission structure formed by the signal line and the ground lines on both sides adopts a progressive transmission line design, that is, a 45° cut is made at the step compensation structure, and the width of the ground lines on both sides of the narrow signal line is increased to ensure the corresponding impedance matching and obtain good echo resistance performance. Moreover, this design can improve the compactness of the single-pole ten-throw switch and reduce the overall device volume.

[0030] Further, if Figure 3 As shown, preferably, the upper electrode 24 of the MEMS switch is a triangular structure, which reduces the elastic coefficient by reducing the width of the cantilever beam, and opens a plurality of openings 202 on the upper electrode 24 of the MEMS switch, thereby reducing the air damping of the switch pull-down to obtain a lower driving voltage. Compared with the traditional upper electrode, the front metal contact area of ​​the structure is much smaller than the transmission line width, and the smaller contact area will reduce the adhesion between metals, increase the contact pressure, and provide better isolation.

[0031] Furthermore, preferably, the upper electrode 24 of the MEMS switch has several openings 202. After adding the above-mentioned release holes, it can make it more fully contact with the sacrificial layer. The openings in the upper electrode plate are conducive to the release of the sacrificial layer during the switch process, thereby improving the switch yield rate. Compared with the traditional upper electrode, the front metal contact area of ​​this structure is much smaller than the transmission line width. The smaller contact area will reduce the adhesion between metals, increase the contact pressure, and provide better isolation.

[0032] Furthermore, the driving electrode 204 is led out from directly below the MEMS switch upper electrode 24 , and by applying voltage to the driving electrodes on different channels, the MEMS switch upper electrode 24 is displaced to contact the MEMS switch contact 203 , so that the corresponding channel is turned on.

[0033] Further, if Figure 4 As shown, it is composed of a disk power divider 26 and equally spaced branches, which are used to reduce the loss of signals during transmission through right-angle bends and reduce the differences in radio frequency performance of each port of the signal.

[0034] Further, preferably, the dielectric substrate 1 is a cubic structure with low conductivity, and the material of the dielectric substrate 1 is glass, ceramic or high-resistance silicon, which has low conductivity and ensures low loss characteristics when transmitting radio frequency signals. Preferably, the materials of the microwave transmission line, the disk power divider 26, the driving electrode 204, the MEMS switch upper electrode 24, the MEMS switch anchor point 201 and the air bridge 25 are all Au.

[0035] Further, if Figure 5 As shown, the air bridge anchor points 301 are connected by air bridges 25, and the air bridges 25 are used to suppress the slot line mode caused by the asymmetry of the coplanar waveguide ground line. At the same time, the air bridge 25 needs to be installed above the step compensation cut angle, and the introduced parallel capacitance is reduced by the step compensation structure. Preferably, the installation of the air bridge 25 will introduce parallel capacitance, which is then reduced by using the step compensation structure, that is, reducing the width of part of the signal line to achieve matching of the transmission structure.

[0036] Further, if Figure 6 As shown in the figure, when the first to tenth output channels are turned on in sequence and the other channels are turned off, the insertion loss of the turned-on channels and the isolation of the remaining channels are simulated. The simulation results show that in the 1-60GHz frequency band of this embodiment, the insertion loss of the output ports on both sides of the input end is <2dB, the insertion loss of the other eight ports is ≤0.59dB, and the isolation of all ports is >30dB.

[0037] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. A broadband RF MEMS single-pole ten-throw switch in the L-U band, characterized in that: The invention comprises a dielectric substrate (1), an input signal line (2), a first output signal line (5), a second output signal line (7), a third output signal line (9), a fourth signal output line (11), a fifth signal output line (13), a sixth signal output line (15), a seventh signal output line (17), an eighth signal output line (19), a ninth signal output line (21), and a tenth signal output line (23); the input signal line (2) is arranged on the dielectric substrate (1); a disk power divider (26) is arranged at the end of the input signal line (2); and a first branch (401), a second branch (402), a third branch (403), a fourth branch (404), a fifth branch (405), and a sixth branch (15). The first branch (401) is connected to a first output signal line (5), the second branch (402) is connected to a second output signal line (7), the third branch (403) is connected to a third output signal line (9), the fourth branch (404) is connected to a fourth signal output line (11), the fifth branch (405) is connected to a fifth signal output line (13), the sixth branch (406) is connected to a sixth signal output line (15), the seventh branch (407) is connected to a seventh signal output line (17), the eighth branch ( The first branch (408) is connected to an eighth signal output line (19), the ninth branch (409) is connected to a ninth signal output line (21), and the tenth branch (410) is connected to a tenth signal output line (23); the first ground line (3) and the second ground line (4) are equidistantly arranged on both sides of the input signal line (2), the second ground line (4) and the third ground line (6) are equidistantly arranged on both sides of the first output signal line (5), the third ground line (6) and the fourth ground line (8) are equidistantly arranged on both sides of the second output signal line (7), the fourth ground line (8) and the fifth ground line (10) are equidistantly arranged on both sides of the third output signal line (9), and the fifth ground line (10) and the fifth ground line (11) are equidistantly arranged on both sides of the fourth signal output line (11). a sixth ground line (12), a sixth ground line (12) and a seventh ground line (14) are equidistantly arranged on both sides of the fifth signal output line (13), a seventh ground line (14) and an eighth ground line (16) are equidistantly arranged on both sides of the sixth signal output line (15), an eighth ground line (16) and a ninth ground line (18) are equidistantly arranged on both sides of the seventh signal output line (17), a ninth ground line (18) and a tenth ground line (20) are equidistantly arranged on both sides of the eighth signal output line (19), a tenth ground line (20) and an eleventh ground line (22) are equidistantly arranged on both sides of the ninth signal output line (21), and the eleventh ground line (22) and the first ground line (3) are equidistantly arranged on both sides of the tenth signal output line (23);The first output signal line (5), the second output signal line (7), the third output signal line (9), the fourth output signal line (11), the fifth output signal line (13), the sixth output signal line (15), the seventh output signal line (17), the eighth output signal line (19), the ninth output signal line (21), and the tenth output signal line (23) are all provided with a MEMS switch anchor point (201), and the first branch (401), the second branch (402), the third branch (403), the fourth branch (404), the fifth branch (405), the sixth branch (406) The first branch (406), the seventh branch (407), the eighth branch (408), the ninth branch (409), and the tenth branch (410) are all provided with MEMS switch contacts (203); the MEMS switch anchor point (201) is fixedly connected to one end of the MEMS switch upper electrode (24); the other end of the MEMS switch upper electrode (24) is arranged directly above the MEMS switch contact (203); the MEMS switch upper electrode (24) is a triangular structure, and a plurality of openings (202) are provided on the MEMS switch upper electrode (24). ; 2. The L-U band wideband RF MEMS single-pole ten-throw switch according to claim 1, characterized in that: A driving electrode (204) is led out from below the upper electrode (24) of the MEMS switch.

3. The L-U band wideband RF MEMS single-pole ten-throw switch according to claim 1, characterized in that: Air bridge anchor points (301) are arranged above the first ground wire (3), the second ground wire (4), the third ground wire (6), the fourth ground wire (8), the fifth ground wire (10), the sixth ground wire (12), the seventh ground wire (14), the eighth ground wire (16), the ninth ground wire (18), the tenth ground wire (20) and the eleventh ground wire (22), and the air bridge anchor points (301) are connected by air bridges (25).

4. The L-U band wideband RF MEMS single-pole ten-throw switch according to claim 1, characterized in that: The dielectric substrate (1) is made of glass, ceramic or high-resistance silicon.

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