JP4419651B2 - High frequency element - Google Patents

Description

  The present invention relates to a high frequency device having a high frequency signal device and a DC voltage supply means for supplying a DC bias voltage to the high frequency signal device.

  For example, when supplying the same DC bias voltage to a plurality of high frequency circuit blocks in series or in parallel, if a simple line is used, a high frequency signal (hereinafter referred to as an RF signal) flows on the DC power supply wiring, and signal noise is generated. The level is expected to rise. Conventionally, however, these adverse effects have not been sufficiently considered or ignored in most cases. When it is desired to avoid such an adverse effect, a completely independent DC power supply circuit is used, but this increases the cost of the power supply.

For example, a high-frequency filter configured using a MEMS (micro electro mechanical system) element has been proposed. In such a high-frequency filter, a DC bias voltage is supplied. It is difficult to obtain good filter characteristics. A high-frequency filter using a MEMS element has been proposed by research institutions such as the University of Michigan (Non-Patent Document 1).
C. T. T. -Nguyen, Micromechanical components for miniaturized low-power communications (invited plenary), proceedings, 1999 IEEE MTT-S International Msp.

  When handling weak signals in the high frequency region, for example, when filtering high frequency (RF) signals, signal leakage bypassing circuits other than the signal path significantly degrades the signal / noise ratio of the filtered signal. . Therefore, in the case of an element in which it is inevitable to install a circuit portion that is electrically coupled to an RF signal line such as a direct current (DC) power supply circuit, a detour circuit other than the signal path should be removed in an effective sense. Is the most important issue.

Further, a description will be given with reference to a comparative example of a prior art resonator using the electrostatic drive beam type MEMS element shown in FIGS. FIG. 13 shows an equivalent circuit of the MEMS electrostatic drive beam type resonator, and FIG. 15 shows a schematic configuration of the MEMS electrostatic drive beam type resonator.

  In the MEMS beam type resonator 1 shown by the equivalent circuit of FIG. 13, the high-frequency signal line 2 is constituted by a microstrip line including a signal line 3 and a ground line 4 that is grounded. And a required DC bias voltage from the DC power supply circuit 6 is applied between the vibrating electrode (driving portion) of the vibrator 5 and the input electrode of the lower electrode. . The actual DC voltage is applied between the ground plane and the driving portion, and a radio frequency (RF) signal is applied between the input electrode and the ground plane. Zs represents the combined impedance of the MEMS beam type vibrator 5, and C 1 represents the stray capacitance of the DC power supply wiring 7.

  As shown in FIG. 15, the MEMS beam type vibrator 5 has a lower electrode, that is, an input electrode 13 and an output electrode 14 formed on a semiconductor substrate 11 with an insulating film 12 therebetween, and is opposed to the input / output electrodes 13 and 14. Thus, an electrode serving as a diaphragm, that is, a so-called beam 16 is formed with the space 15 interposed therebetween. The beam 16 straddles the input / output electrodes 13, 14 in a bridge shape and is connected to a wiring layer 18 disposed outside the input / output electrodes 13, 14 at both ends with support portions (so-called anchor portions) 19 [19 a, 19b]. A conductive layer 22 serving as a ground line is formed on the back surface of the semiconductor substrate 11 via an insulating film 21.

  A DC power supply circuit 6 is connected to the beam 16 via the DC power supply wiring 7, and a required DC bias voltage V 1 is supplied to the beam 16. (An RF signal and a DC voltage may be superimposed and applied to the electrode 13 or 14.) The input terminal Tin is derived to the input electrode 13, and the RF signal is input through the input terminal Tin. An output terminal Tout is derived from the output electrode 14, and an RF signal having a target frequency is output from the output terminal Tout. In the MEMS beam vibrator 5, when a high frequency signal is input to the input electrode 13, the beam 16 resonates due to electrostatic force generated between the beam 16 supplied with the DC bias voltage and the input electrode 13, and the output electrode 14. To output an RF signal having a target frequency.

In the MEMS beam resonator 1 having the above-described configuration, a plurality of, for example, 100 vibrators 5 described above are configured in parallel. When the RF signal is transmitted from the input electrode 13 to the output electrode 14 and is output, a part 20 of the RF signal leaks around the DC power supply wiring 7, causing interference of the RF signal and adversely affecting the resonator characteristics. give. FIG. 14 shows the frequency dependence of the transmission characteristic value S21 (S parameter) of the MEMS beam resonator 1 at this time. In the measured MEMS beam resonator 1, the center frequency of the vibrator group is 98 MHz, the combined impedance Zs of the vibrator 5 is composed of a series resistance Rx = 5 kΩ, and a grounded capacitance C 0 = 1 × 10 ¹⁵ F. −30 V was applied from the DC power supply circuit 6 to the beam 16 of the vibrator 5. According to the MEMS beam type resonator 1, in addition to the original peak 24 near 98 MHz, noise (so-called ghost) peaks 25 and 26 having the same intensity as that of the resonance peak were observed.

  In view of the above, the present invention provides a high-frequency element that suppresses leakage of a high-frequency signal to other than the signal path and improves the signal / noise ratio of the high-frequency signal.

The high-frequency device according to the present invention includes a filter having a transducer group in which a plurality of MEMS beam-type transducers are arranged in parallel, and each beam of the plurality of MEMS beam-type transducers connected to the transducer group via a DC power supply wiring. And a common DC power supply circuit for supplying a DC bias voltage to the filter, and a high-frequency signal line connected to the filter. Furthermore, the present invention includes an element that is interposed between the DC power supply wiring and the beam of the vibrator group and makes impedance mismatch between the high-frequency signal line and the DC power supply wiring.

The high-frequency element according to the present invention is composed of a series vibrator having a vibrator group in which a plurality of MEMS beam vibrators are arranged in parallel and a shunt vibrator having a vibrator group in which a plurality of MEMS beam vibrators are arranged in parallel. DC bias is applied to each beam of a plurality of MEMS beam-type vibrators of a vibrator group that is connected to the series type filter and the series vibrator and the shunt vibrator via a DC power supply wiring. It has one common DC power supply circuit that supplies voltage. The present invention further includes a high-frequency signal line connected to the ladder filter, the series vibrator beam and the DC power supply wiring, and the shunt vibrator beam and the DC power supply wiring, respectively. An element that causes impedance mismatch between the signal line and the DC power supply wiring is provided.

A high-frequency device according to the present invention includes a resonator having a vibrator group in which a plurality of MEMS beam-type vibrators are arranged in parallel, and the vibrator group connected to each other via a DC power supply wiring. One common DC power supply circuit for supplying a DC bias voltage to the beam and a high-frequency signal line connected to the resonator . Furthermore, the present invention includes an element that is interposed between the DC power supply wiring and the beam of the vibrator group and makes impedance mismatch between the high-frequency signal line and the DC power supply wiring.

A high-frequency device according to the present invention includes a composite vibrator type filter having a vibrator group in which a plurality of complex MEMS beam type vibrators each having a beam of a plurality of MEMS beam vibrators connected to each other, and a direct current applied to the vibrator group. One common DC power supply circuit that is connected via a power supply wiring and supplies a DC bias voltage to each beam of the plurality of MEMS beam type vibrators, and a high-frequency signal line connected to the composite vibrator type filter. Furthermore, the present invention includes an element that is interposed between the DC power supply wiring and the beam of the vibrator group and makes impedance mismatch between the high-frequency signal line and the DC power supply wiring.

According to the high frequency device of the present invention , a vibrator group in which a plurality of MEMS beam type vibrators are arranged in parallel, and the vibrator group are connected to each beam of the plurality of MEMS beam type vibrators through a DC power supply wiring. It has one common DC power supply circuit that supplies a DC bias voltage. And by inserting an element that makes impedance mismatch between the high frequency signal line and the DC power supply line between the DC power supply line and the beam of the vibrator group , leakage of the high frequency signal to the DC power supply line is prevented. It is suppressed. Therefore, high-frequency signal interference caused by bypassing the high-frequency signal through the DC power supply wiring can be minimized, and the signal / noise ratio of the high-frequency signal can be improved. That is, a high frequency device with a good signal / noise ratio can be realized. In addition, since an independent power supply is required, the cost associated with the power supply can be reduced.

According to the high frequency device of the present invention, a ladder type filter composed of a series vibrator and a shunt vibrator formed of a vibrator group in which a plurality of MEMS beam vibrators are arranged in parallel, and the series vibrator and the shunt vibrator One common DC power supply circuit is connected through a DC power supply wiring and supplies a DC bias voltage to each beam of each of the plurality of MEMS beam type vibrators. Then, a DC power supply wiring for a high-frequency signal is inserted between each of the series vibrator and the shunt vibrator and the DC power supply wiring by interposing an element having impedance mismatch between the high-frequency signal transmission line and the DC power supply wiring. Leakage is suppressed. Therefore, high-frequency signal interference caused by bypassing the high-frequency signal through the DC power supply wiring can be minimized, and the signal / noise ratio of the high-frequency signal can be improved. In addition, since an independent power supply is required, the cost associated with the power supply can be reduced.

According to the high frequency device of the present invention, a resonator having a group of transducers in which a plurality of MEMS beam type transducers are arranged in parallel, and the plurality of MEMS beam type transducers are connected to the transducer group via a DC power supply wiring. One common DC power supply circuit for supplying a DC bias voltage to each of the beams is provided. And by inserting an element that makes impedance mismatch between the high frequency signal line and the DC power supply line between the DC power supply line and the DC power supply line, leakage of the high frequency signal to the DC power supply line is prevented. It is suppressed. Therefore, high-frequency signal interference caused by bypassing the high-frequency signal through the DC power supply wiring can be minimized, and the signal / noise ratio of the high-frequency signal can be improved. In addition, since an independent power supply is required, the cost associated with the power supply can be reduced.

According to the high frequency device of the present invention, a composite vibrator type filter having a vibrator group in which a plurality of composite MEMS beam type vibrators each having a plurality of MEMS beam type vibrators connected to each other are arranged in parallel, and the vibrator group And a common DC power supply circuit for supplying a DC bias voltage to each beam of the plurality of MEMS beam type vibrators. Then, by interposing an element that causes impedance mismatch between the high frequency signal line and the DC power supply line between the DC power supply line and the DC power supply line, leakage of the high frequency signal to the DC power supply line is suppressed. The Therefore, high-frequency signal interference caused by bypassing the high-frequency signal through the DC power supply wiring can be minimized, and the signal / noise ratio of the high-frequency signal can be improved. In addition, since an independent power supply is required, the cost associated with the power supply can be reduced.

  The high-frequency element according to the present embodiment appropriately divides a high-frequency circuit block when a DC bias voltage is supplied to one or a plurality of high-frequency circuit blocks (for example, a parallel vibrator), It connects with the impedance different from the impedance of RF signal line seen from the direct current electric power feeding part which makes a part of RF signal line inside. When the DC power supply wiring is formed using such a connection method, the leakage from the signal line to which the DC bias voltage and the high frequency signal are mixedly applied in the high frequency circuit block to the outside of the block through the DC power supply circuit is minimized. Can be suppressed. Although the best connection method is to connect the DC power supply wiring through a low-pass filter, a sufficient effect can be obtained even with only a difference in resistance. In particular, when a high-frequency element is configured using a MEMS (micro electro mechanical system) beam type transducer group, since a very small direct current flows through the direct current feed line, a considerably large resistance, for example, a resistance of several MΩ is provided. Is inserted between the vibrator group and the DC power supply wiring, a voltage drop due to the resistance does not occur, so that an effective impedance mismatch can be realized.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an equivalent circuit of a first embodiment in which a high-frequency element according to the present invention is applied to a high-frequency filter. The high-frequency filter according to the present embodiment is a one-stage ladder type filter.
In the ladder filter 31 of the present embodiment, the high-frequency signal line 32 is constituted by a microstrip line, and a plurality of vibrators (vibrator group) paralleled in series between the input terminals Tin and Tout of the signal line 33. Is connected to the output side of the series vibrator 35 and a ground line 34. Similarly, a shunt vibrator 36 comprising a plurality of vibrators (vibrator groups) connected in parallel is connected. Is done. The series vibrator 35 and the shunt vibrator 36 are configured to operate by supplying a DC bias voltage. Therefore, a DC voltage supply means, for example, a DC power supply circuit having a DC power supply circuit 37 and a DC power supply line 38 is provided, and the series vibrator 35 and the shunt vibration are provided from the DC power supply circuit 37 through the DC power supply circuit, that is, the DC power supply wiring 38. It is connected to a driving part of the child 36 which becomes a part of a signal line 33 described later. The DC power supply circuit 37 may have, for example, a circuit configuration that is converted from an alternating current to a constant voltage / DC and supplied, or a circuit configuration that is converted from a direct current into a constant voltage / DC voltage and supplied.

  In the present embodiment, in particular, there is an impedance mismatch between the impedance of the series vibrator 35 and the shunt vibrator 36 as viewed from the DC feed terminal side of the signal line 33 and the impedance of the series feed wiring 38. It is configured as follows. That is, an element for forming an impedance mismatch is connected between the signal line 33 in the series vibrator 35 and the shunt vibrator 36 and the series power supply wiring 38. As this element, resistance elements R1 and R2 are used in this example.

  The series vibrator 35 and the shunt vibrator 36 are formed of MEMS electrostatic drive beam vibrators. 2A and 2B show a schematic configuration of a MEMS electrostatic drive beam type vibrator. In the MEMS electrostatic drive beam type vibrator 50, the lower electrode, that is, the input electrode 43 and the output electrode 44 are formed on the semiconductor substrate 41 via the insulating film 42 as described above, and the input electrode 43 and the output electrode 44 are formed. A beam-type vibrating electrode (hereinafter referred to as a beam) 46 is formed as a vibrating plate across the space 45. Both ends of the beam 46 are integrally supported by the support portions 49A and 49B so as to cross the input / output electrodes 43 and 44 in a bridge shape and to be connected to the wiring layer 48 disposed outside the input / output electrodes 43 and 44. . A conductive layer 52 is formed on the back surface of the semiconductor substrate 41 to be the ground wiring 34 that is grounded through the insulating film 51.

In the MEMS electrostatic drive beam type vibrator 50, as shown in FIG. 3, a DC power supply circuit 37 is connected between a drive portion 46 that is a part of the signal line 33 and a conductive layer 52 that is a wiring 34 that is grounded. Then, a required DC bias voltage is applied to the beam 46. In this embodiment, as shown in FIGS. 1 and 3, an element for forming an impedance mismatch, in this example, a resistance element R having a required resistance value is connected to the DC power supply wiring 38 and the signal line 33. For example, it is connected to the beam 46 which becomes a part of the beam. Therefore, in FIG. 1, the resistance element R1 is connected between the beam 46 (see FIG. 3) of the series vibrator 35 and the DC power supply wiring 38, and the beam 46 (see FIG. 3) of the shunt vibrator 36 and the DC power supply. A resistance element R 2 is connected between the wiring 38.

The serial vibrator 35 in FIG. 1 is configured by paralleling a plurality of, for example, 40 individual MEMS electrostatic drive beam vibrators 50 as shown in FIG. The shunt vibrator 36 is configured by paralleling a plurality of, for example, 160 MEMS beam-type vibrators 50. The combined impedance Zs of the series vibrator 35 is composed of, for example, a series resistance Rx = 5 kΩ and a ground C0 = 1 × 10 ¹³ F. The combined impedance Zp of the shunt vibrator 36 is composed of, for example, a series resistance Rx = 1 kΩ and a grounded capacitance C0 = 8 × 10 ¹³ F. The resistance elements R1 and R2 connected between the beam 46 forming a part of the signal line 33 and the DC power supply line 38 are formed by using, for example, a thin line made of a polycrystalline silicon film, and the resistance values thereof are, for example, R1 and R2. = 1 MΩ. The characteristic impedance of the signal line 33 shown in FIG. 1 is designed to be the same as the combined impedance Zp of the shunt vibrator 36.
The one-stage ladder type high frequency filter 31 of the present embodiment includes a high frequency circuit block including a series vibrator 35 and a shunt vibrator 36 and a DC power supply block including a DC power supply circuit 37 and a DC power supply wiring 38 on the same semiconductor chip. It is formed and configured.

4 to 7 show the filter characteristics of the one-stage ladder type filter 31 represented by the equivalent circuit of FIG. In other words, the frequency dependence of the transmission characteristic value S21 (S parameter) measured by using a network analyzer 3767G manufactured by Advantech Co., Ltd. for a ladder filter 31 manufactured by a silicon semiconductor process and configured using a MEMS beam type transducer group. Show. A DC-15V was applied to the series vibrator (vibrator group) 35 and the shunt vibrator (vibrator group) 36 using a common power source. The resonance frequency of the series vibrator (vibrator group) 35 was set to 98 MHz, and the center frequency of the shunt vibrator (vibrator group) 36 was set to 96 MHz, 95 MHz, and 92 MHz, which were lower by 2 MHz, 3 MHz, and 6 MHz, respectively.
FIG. 4 is a filter characteristic showing shunt frequency dependence (overlapping curves with different shunt frequencies shown in FIGS. 5 to 7). 5, FIG. 6, and FIG. 7 show enlarged frequency characteristics corresponding to the main part A of FIG. 4 when the center frequency of the shunt vibrator 36 is 96 MHz, 95 MHz, and 92 MHz, respectively. As is apparent from FIG. 4, in any shunt frequency, substantially the same curve without ghost (noise) is exhibited, and in particular, at the peak portion of resonance and anti-resonance, the same curve is obtained, and the expected frequency characteristics without noise. Is shown. The reason why the effect of the shunt oscillator 36 can be observed only indefinitely is that the input impedance of the network analyzer is 50Ω.

  According to the one-stage ladder filter 31 of the first embodiment, the beam 46 forming a part of the signal line 33 of the series vibrator 35 and the shunt vibrator 36 formed by the MEMS electrostatic drive beam type vibrator. By connecting resistance elements R1 and R2 that are impedance mismatched between the DC power supply wiring 38 and the DC power supply wiring 38, the bypass of the high frequency signal through the DC power supply wiring 38 is suppressed, and the signal / noise ratio of the filtered high frequency signal is increased. Can be improved. In addition, since a plurality of independent power supplies are not required, the cost associated with the power supplies can be reduced.

FIG. 8 is an equivalent circuit of a second embodiment in which the high-frequency element according to the present invention is applied to a high-frequency filter. The high frequency filter according to the present embodiment is a two-stage ladder filter.
The ladder filter 61 according to the present embodiment has a series vibrator 651 constituted by a plurality of vibrators (vibrator groups) respectively arranged in parallel on the high-frequency signal line 32 constituted by a microstrip line as described above. , 652 are connected in two stages to a ladder type filter composed of shunt vibrators 661 and 662 each composed of a plurality of vibrators (vibrator groups) arranged in parallel. That is, the series vibrator 651 between the input terminals _{T IN} and the output terminal Tout of the signal line 33 is connected between the output side and the ground line 34 of the series vibrator 651 of the first stage shunt vibrator 661 is connected A ladder type filter is provided, and a series vibrator 652 is connected to the signal line 33 at the subsequent stage, and a shunt vibrator 662 is connected between the output side of the series vibrator 652 and the ground line 34. A filter is provided.

  Each of the series vibrators 651 and 652 and the shunt vibrators 661 and 662 is configured to operate by supplying a DC bias voltage. Therefore, a DC voltage supply means, for example, a DC power supply circuit having a DC power supply circuit 37 and a DC power supply line 38 is provided in the same manner as described above, and the series vibrator is connected from the DC power supply circuit 37 through the DC power supply circuit, that is, the DC power supply wiring 38. 651 and 652 and shunt vibrators 661 and 662 are connected to vibration electrodes that are part of the signal line 33.

  In this embodiment, in particular, there is an impedance mismatch between the impedance of the signal line 33 and the impedance of the series power supply wiring 38 in the series vibrators 651 and 652 and the shunt vibrators 661 and 662. The That is, elements for forming an impedance mismatch, such as resistance elements R3 to R6, are connected between the signal lines 33 in the series vibrators 651 and 652 and the shunt vibrators 661 and 662 and the series power supply wiring 38.

  The serial vibrators 651 and 652 and the shunt vibrators 661 and 662 are configured by the MEMS beam type vibrator 50 shown in FIG. A resistance element R3 is connected between the beam 46 of the first-stage series vibrator 651 and the DC power supply wiring 38, and a resistance element R4 is connected between the beam 46 of the shunt vibrator 661 and the DC power supply wiring 38. Is done. A resistance element R5 is connected between the beam 46 of the second stage series vibrator 652 and the DC power supply wiring 38, and a resistance element R6 is connected between the beam 46 of the shunt vibrator 662 and the series power supply wiring 38. Is done.

The series vibrators 661 and 662 in FIG. 8 are configured by paralleling a plurality of, for example, 100 individual MEMS electrostatic drive beam vibrators 50 as shown in FIG. The shunt vibrators 661 and 662 are configured by arranging a plurality of, for example, 400 MEMS electrostatic drive beam vibrators 50 in parallel. The impedance Zs of the series vibrators 651 and 652 is composed of, for example, a series resistance Rx = 5 kΩ and a grounding capacitance C0 = 1 × 10 ¹³ F. The impedance Zp of the shunt vibrators 661 and 662 is composed of, for example, a series resistance Rx = 1 kΩ and a grounding capacitance C0 = 8 × 10 ¹³ F. The resistance elements R3, R4, R5, and R6 are formed using, for example, a thin line made of a polycrystalline silicon film, and the resistance values thereof can be set to R3, R4, R5, R6 = 1 MΩ, for example. The characteristic impedance of the signal line 33 shown in FIG. 8 is designed to be the same as the impedance Zp of the shunt vibrators 661 and 662.
In the high frequency filter 61 of the present embodiment, the high frequency circuit block including the series vibrators 651 and 652 and the shunt vibrators 661 and 662 and the DC power supply block including the DC power supply circuit 37 and the DC power supply wiring 38 are arranged on the same semiconductor chip. It is formed and configured.

  FIG. 9 shows filter characteristics of a two-stage ladder filter 61 represented by the equivalent circuit of FIG. That is, the frequency dependence of the transmission characteristic value S21 (S parameter) measured by using a network analyzer 3767G manufactured by Advantech Co., Ltd. for a ladder filter 61 configured using a MEMS beam type vibrator group manufactured by a silicon semiconductor process. Indicates. A DC-15V was applied to the series vibrators (vibrator groups) 651 and 652 and the shunt vibrators (vibrator groups) 661 and 662 using a common power source. The resonance frequency of the series vibrators (vibrators) 651 and 652 was set to 98 MHz, and the center frequency of the shunt vibrators (vibrators group) 661 and 662 was set to 94 MHz, which is 4 MHz lower than that of the series vibrators. . As is apparent from the characteristic curve of FIG. 9, the expected frequency characteristic without noise is shown. The reason why the effects of the shunt oscillators 661 and 662 can be observed only indefinitely is that the input impedance of the network analyzer is 50Ω.

  According to the two-stage ladder filter 61 of the second embodiment, a part of the signal line 33 of the series vibrators 651 and 652 and the shunt vibrators 661 and 662 formed of MEMS electrostatic drive beam vibrators. By connecting resistance elements R3, R4, R5, and R6, which are impedance mismatches, between the beam 46 and the DC power supply wiring 38, the bypass of the high-frequency signal through the DC power supply wiring 38 is suppressed and filtered. The signal / noise ratio of the high frequency signal can be improved. In addition, since a plurality of independent power supplies are not required, the cost associated with the power supplies can be reduced.

  FIG. 10 is an equivalent circuit of a third embodiment in which the high-frequency element according to the present invention is applied to a high-frequency resonator. The high-frequency resonator 71 according to the present embodiment includes a plurality of vibrators (vibrator group) arranged in parallel between the input and output terminals Tin and Tout of the signal line 73 of the high-frequency signal line 72 configured by a microstrip line. And a beam 46 (for example, as shown in FIG. 3), which is a part of the signal line of the vibrator 75 and the DC power supply wiring 78 from the DC power supply circuit 77 for operating the vibrator 75. And an element that effectively mismatches the impedance, in this example, a low-pass filter 79 is connected. The vibrator 75 is configured by the MEMS beam type vibrator 50 of FIG. 2 as described above.

The vibrator 75 in FIG. 10 is configured by arranging a plurality of, for example, 100 MEMS beam type vibrators 50 in parallel as described above. The combined impedance Zs of the vibrator 75 includes a series resistance Rx = 5 kΩ and a grounded capacitance C0 = 1 × 10 ¹³ F. The characteristic impedance of the signal line 73 of the high-frequency signal line 72 is designed to be the same as the impedance Zs of the vibrator 75. C1 indicates the stray capacitance of the DC power supply wiring 78 or the capacitance forming a part of the low-pass circuit.

FIG. 11 shows the resonance characteristics of the high-frequency resonator 71 represented by the equivalent circuit of FIG. That is, the transmission characteristic value S21 (S parameter) measured by using a network analyzer 3767G manufactured by Advantech Co., Ltd. for the high frequency resonator 71 configured using the MEMS electrostatic drive beam type vibrator group 50 manufactured by the silicon semiconductor process. ) Frequency dependence. A DC power supply circuit 77 incorporating a low-pass filter 79 was used for the vibrator group, and DC-20V was applied. The beam 46 of the vibrator 75, which is a part of the signal line 73, and the low-pass filter 79 on the DC power supply circuit 77 side are connected by an Au fine wire by a wire bond method.
As is apparent from FIG. 10, a resonance curve without noise and having a peak near 98 MHz can be observed.

  In the example of FIG. 10, the low-pass filter 79 is used as an element for effectively making the impedance mismatch, but an LC circuit, a resistance element, or the like can also be used.

  According to the high frequency resonator 71 of the third embodiment, the vibrator 75 formed of the MEMS electrostatic drive beam type vibrator has a low pass between the beam 46 that is a part of the signal line 73 and the DC power supply wiring 78. By connecting the filter 79, unnecessary reflection of the high-frequency signal through the DC power supply wiring 78 is suppressed, and the signal / noise ratio of the high-frequency signal at the resonance frequency can be improved.

  In the above example, the present invention is applied to a ladder type filter or resonator in which a plurality of MEMS electrostatic drive beam type vibrators are electrically coupled. However, in addition, a plurality of MEMS beam type vibrators are mechanically coupled. It can be applied to the composite electrostatic drive vibrator type filter constituted by. In this case, the DC bias voltage to the vibrator or vibrator group constituting the composite vibrator type filter is supplied in a state inconsistent with the impedance of the high-frequency signal line. As a result, as described above, the signal / noise ratio of the filtered high-frequency signal can be improved, and since a plurality of independent power supplies are not required, the cost associated with the power supply can be reduced.

FIG. 12 shows an electrostatically driven beam type vibrator according to a fourth embodiment in which the high frequency device according to the present invention is applied to a high frequency resonator. This electrostatic drive beam type vibrator corresponds to a composite electrostatic drive vibrator type filter in which the plurality of MEMS beam type vibrators are mechanically coupled.
The high-frequency resonator 81 according to the present embodiment has a lower electrode 83 serving as an output on a substrate 82 shown in FIG. 12B and an upper electrode serving as an input disposed so as to face the space 84 with a space 84 therebetween, a so-called beam 85. Two MEMS filters 86 having a structure are arranged so that the beams 85 are parallel as shown in FIG. 12A. The two MEMS filters are formed such that a part of the two parallel beams 85 [85A, 85B] are connected via the connecting portion 86, and the lower electrodes 83 [83A, 83B] are independently formed. It becomes a structure. As a position where the beams 85A and 85B are connected, a vibration node (a fixed point) is selected. In the high-frequency resonator 81 configured as described above, one lower electrode 83A serves as a signal input, and the other lower electrode 83B serves as an output. In this case, a DC bias voltage is applied to the beam 85.
In the present embodiment, for example, a plurality of composite vibrators having such a configuration can be installed in parallel, and high-frequency signals can be filtered in parallel.
In the high frequency resonator 81 according to the present embodiment, the DC bias voltage to the vibrator or vibrator group constituting the composite vibrator type filter is supplied in a state inconsistent with the impedance of the high frequency signal line. The configuration is the same as described above.
The high frequency resonator 81 according to the present embodiment also has the same effects as described above.

  When composing a filter composed of multiple vibrators such as the ladder type filter and the composite vibrator type filter described above, adjacent vibrators (vibrators composed of a plurality of parallel vibrators (vibrator group)) By sufficiently shortening the length of the wiring between the wirings and the length of the wiring between the filters of the plurality of stages as compared with the wavelength of the high frequency signal to be handled, it is possible to suppress signal distortion caused by the delay of the high frequency signal. .

  In the above example, the present invention is applied to a high-frequency filter and a high-frequency resonator. However, the present invention can be applied to a high-frequency switch using a beam-type MEMS element, a passive element such as a distributor, a MEMS (micro mechanical system), and the like. it can.

The above-described high-frequency device of the present invention is configured by forming a high-frequency circuit block constituting these and a power supply circuit block for operating the high-frequency circuit block on the same wafer chip, that is, one semiconductor chip. can do. Alternatively, the high-frequency device of the present invention can be configured, for example, by including a semiconductor chip on which a high-frequency circuit block is formed and a semiconductor chip on which the power supply circuit block is formed, and connecting both chips with a wire.
The means for making the impedance mismatch may be inserted on the DC power supply circuit side or on the high frequency signal element side.

1 is an equivalent circuit diagram showing a first embodiment in which a high-frequency element according to the present invention is applied to a ladder filter having a one-stage configuration. A is a schematic plan view of a MEMS electrostatic drive type beam transducer applied to the present invention. B is a schematic cross-sectional view of a MEMS electrostatic drive type beam vibrator applied to the present invention. FIG. FIG. 3 is a schematic configuration diagram in which a DC power supply circuit and means for impedance mismatching are connected when the MEMS electrostatic drive beam type vibrator according to the present invention is used. FIG. 2 is a filter characteristic diagram showing the frequency dependence of the transmission characteristic value of the one-stage ladder filter of FIG. 1. FIG. 5 is an enlarged view of the main part of FIG. 4 when the center frequency of the shunt transducer group in the equivalent circuit of FIG. 1 is 92 MHz. FIG. 5 is an enlarged view of the main part of FIG. 4 when the center frequency of the shunt transducer group in the equivalent circuit of FIG. 1 is 95 MHz. FIG. 5 is an enlarged view of the main part of FIG. 4 when the center frequency of the shunt transducer group in the equivalent circuit of FIG. 1 is 96 MHz. FIG. 6 is an equivalent circuit diagram showing a second embodiment in which the high-frequency element according to the present invention is applied to a two-stage ladder filter. FIG. 9 is a filter characteristic diagram illustrating the frequency dependence of the transmission characteristic value of the two-stage ladder filter of FIG. 8. It is the equivalent circuit which shows 3rd Embodiment which applied the high frequency element which concerns on this invention to the high frequency resonator. It is a characteristic view which shows the frequency dependence of the transmission characteristic value of the high frequency resonator of FIG. A and B are a plan view and a sectional view showing a fourth embodiment in which the high-frequency element according to the present invention is applied to a high-frequency resonator. It is an equivalent circuit schematic of the high frequency resonator which concerns on a comparative example. It is a characteristic view which shows the frequency dependence of the transmission characteristic value of the high frequency resonator of FIG. It is a schematic sectional drawing of the MEMS electrostatic drive beam type vibrator applied to the comparative example of FIG.

31 .. One-stage ladder type filter, 32..High-frequency signal line, 33..Signal line, 34..Ground line, 35..Series vibrator, 36.Shunt vibrator, 37..DC power supply circuit , 38 .. DC feed line, 50 .. MEMS beam type vibrator, 41 .. Semiconductor substrate, 42, 51 .. Insulating film, 43 .. Input electrode, 44 .. Output electrode, 45. .. Beam, 48 .. Wiring layer, 19a, 19b .. Supporting part, 52 .. Conductive layer to be ground line, 61 .. Ladder type filter of two-stage configuration, 651, 652 .. Series vibrator, 661, 662 ..Shunt vibrators, R1 to R6 ..Resistance element, 71 ..High frequency resonator, 72 ..High frequency signal line, 73 ..Signal line, 74 ..Ground line, 77 ..DC power supply circuit, 78 DC feed line, 79 ... -Pass filter, C1

Claims (8)

A filter having a vibrator group in which a plurality of MEMS beam-type vibrators are arranged in parallel;
A common DC power supply circuit connected to the vibrator group via a DC power supply wiring and supplying a DC bias voltage to each beam of the plurality of MEMS beam type vibrators;
A high-frequency signal line connected to the filter;
A high-frequency element having an element that is interposed between the DC power supply wiring and the beam of the vibrator group and makes impedance mismatch between the high-frequency signal line and the DC power supply wiring. A ladder-type filter including a series vibrator by a vibrator group in which a plurality of MEMS beam-type vibrators are arranged in parallel, and a shunt vibrator by a vibrator group in which a plurality of MEMS beam-type vibrators are arranged in parallel;
A DC bias voltage is applied to each beam of the plurality of MEMS beam-type vibrators of the vibrator group that is connected to the series vibrator and the shunt vibrator via a DC power supply wiring and constitutes the series vibrator and the shunt vibrator. One common DC power supply circuit to supply;
A high-frequency signal line connected to the ladder filter;
An impedance is inserted between the beam of the series vibrator and the DC power supply wiring, and between the beam of the shunt vibrator and the DC power supply wiring, and between the high-frequency signal line and the DC power supply wiring. A high-frequency element having a mismatching element. A resonator having a vibrator group in which a plurality of MEMS beam-type vibrators are arranged in parallel;
A common DC power supply circuit connected to the vibrator group via a DC power supply wiring and supplying a DC bias voltage to each beam of the plurality of MEMS beam type vibrators;
A high-frequency signal line connected to the resonator ;
A high-frequency element having an element that is interposed between the DC power supply wiring and the beam of the vibrator group and makes impedance mismatch between the high-frequency signal line and the DC power supply wiring. A composite vibrator type filter having a vibrator group in which a plurality of composite MEMS beam type vibrators connected with beams of a plurality of MEMS beam type vibrators are arranged in parallel;
A common DC power supply circuit connected to the vibrator group via a DC power supply wiring and supplying a DC bias voltage to each beam of the plurality of MEMS beam type vibrators;
A high-frequency signal line connected to the composite vibrator type filter;
A high-frequency element having an element that is interposed between the DC power supply wiring and the beam of the vibrator group and makes impedance mismatch between the high-frequency signal line and the DC power supply wiring. The high-frequency device according to claim 1, wherein the filter, the DC power supply circuit having the DC power supply circuit and the DC power supply wiring, and the impedance mismatching element are formed on the same wafer chip. The high frequency device according to claim 2, wherein the ladder filter, the DC power supply circuit having the DC power supply circuit and the DC power supply wiring, and the impedance mismatching element are formed on the same wafer chip. The high-frequency device according to claim 3, wherein the resonator, the DC power supply circuit having the DC power supply circuit and the DC power supply wiring, and the impedance mismatching element are formed on the same wafer chip. 5. The high frequency device according to claim 4, wherein the composite vibrator type filter, the DC power supply circuit having the DC power supply circuit and the DC power supply wiring, and the impedance mismatching element are formed on the same wafer chip. .

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