CN106711164A - Indirect heating type microwave signal detector for clamped beam - Google Patents

Abstract

The fixed beam indirect heating microwave signal detector of the present invention is composed of a six-port fixed beam coupler, a channel selection switch, a microwave frequency detector, and a microwave phase detector; the six-port fixed beam coupler is composed of a coplanar waveguide, a dielectric Layer, air layer and fixed beam; the power coupling degrees of the six-port fixed beam coupler from the first port to the third port, the fourth port, the first port to the fifth port, and the sixth port are the same respectively. The signal is input through the first port, the indirect heating microwave power detector is output through the second port, the indirect heating microwave phase detector is output through the fourth port and the sixth port, and the channel selection switch is output through the third port and the fifth port; The seventh port and the eighth port of the channel selection switch are connected to the indirect heating microwave power sensor, and the ninth port and the tenth port of the channel selection switch are connected to the microwave frequency detector; finally, a chip can simultaneously monitor the power, phase and frequency of the microwave signal Detection of three microwave parameters.

Description

Fixed-beam indirect heating microwave signal detector

technical field

The invention provides a fixed beam indirect heating type microwave signal detector, which belongs to the technical field of micro-electromechanical systems.

Background technique

Parameters such as the amplitude, power, and frequency of microwave signals are traditional measurement parameters. Microwave signal phase measurement is not only related to power measurement, but also plays an important role in microwave measurement. As the frequency increases, the wavelength of the signal is gradually approaching the size of various components in the circuit. The voltage and current in the circuit exist in the form of waves. The phase delay of the signal makes the voltage and current at different positions in the circuit not only at the same time The amplitudes are different, and the voltage and current at the same location are also different at different times. Therefore, it is necessary to grasp and control the phase of the signal in the microwave frequency band, and the phase of the microwave signal has become an important measurement parameter. The present invention is to design a single chip based on the Si process to simultaneously detect the microwave power, phase and frequency of the fixed-beam indirect heating microwave signal detector.

Contents of the invention

Technical problem: The object of the present invention is to provide a fixed beam indirect heating microwave signal detector, which uses a six-port fixed beam coupler port to couple and connect different detection function modules, thereby realizing simultaneous detection of microwave signals by one chip The detection of three microwave parameters of power, phase and frequency has the advantages of low power consumption and low cost.

Technical solution: The fixed beam indirect heating microwave signal detector of the present invention is composed of a six-port fixed beam coupler, a channel selection switch, a microwave frequency detector, and a microwave phase detector;

The power coupling degrees from the first port to the third port, the fourth port and the first port to the fifth port and the sixth port of the six-port fixed beam coupler are respectively the same, the signal to be tested is input through the first port, and the second Port output to the first indirect heating microwave power detector, output to the first Wilkinson power combiner and the second Wilkinson power combiner of the microwave phase detector respectively by the fourth port and the sixth port, and combined by the first Wilkinson power The device and the second Wilkinson power combiner are connected to the second indirect heating microwave power detector and the third indirect heating microwave power detector; the third port and the fifth port are output to the seventh port and the channel selection switch of the channel selection switch The eighth port is connected to the second indirect heating microwave power sensor and the third indirect heating microwave power sensor, the ninth port and the tenth port of the channel selection switch are connected to the third Wilkinson power combiner of the microwave frequency detector, and the third Wilkinson The power combiner is connected to the fifth indirect heating microwave power detector, thereby realizing the detection of microwave signal power, phase and frequency.

Among them, the six-port fixed beam coupler is composed of a coplanar waveguide, a dielectric layer, an air layer and a fixed beam across it; the coplanar waveguide is fabricated on the SiO ₂ layer, and the anchor region is fabricated on the coplanar waveguide. The dielectric layer is deposited under the beams, and forms a coupling capacitor structure together with the air layer and the fixed beams. The length of the coplanar waveguide between the two fixed beams is λ/4;

Beneficial effect:

1) The fixed-beam indirect heating microwave signal detector of the present invention integrates three measurement modules of microwave signal power, phase and frequency, and uses the fixed-beam coupler of the six-port fixed-beam coupler to couple the input signal to different The detection function module realizes the detection of three microwave parameters of the power, phase and frequency of the microwave signal at the same time with one chip, which has the benefits of low power consumption and low cost;

2) The fixed-support beam indirect heating microwave signal detector of the present invention uses an indirect heating microwave power sensor to detect the power of microwave signals, and has better microwave characteristics and no DC power consumption;

3) The microwave phase detection module in the present invention uses two Wilkinson power combiners, one Wilkinson power divider and two indirect heating microwave power sensors to realize 0-360° phase detection.

Description of drawings

Fig. 1 is the functional block diagram of the fixed beam indirect heating type microwave signal detector of the present invention,

Figure 2 is a top view of a six-port fixed beam coupler,

Fig. 3 is a sectional view of the AA' direction of the six-port fixed beam coupler in Fig. 2,

Figure 4 is a top view of the channel selection switch,

Fig. 5 is the AA' direction sectional view of Fig. 4 channel selection switch,

Figure 6 is a top view of the Wilkinson power splitter/combiner,

Fig. 7 is a top view of an indirect heating microwave power sensor,

Fig. 8 is a sectional view in the direction of AA' of the indirect heating microwave power sensor in Fig. 7 .

The figure includes: six-port fixed beam coupler 1, channel selection switch 2, microwave frequency detector 3, microwave phase detector 4, first indirect heating microwave power sensor 5-1, second indirect heating microwave power sensor Sensor 5-2, third indirect heating microwave power sensor 5-3, fourth indirect heating microwave power sensor 5-4, fifth indirect heating microwave power sensor 5-5, sixth indirect heating microwave power sensor 5 -6, first Wilkinson power combiner 6-1, second Wilkinson power combiner 6-2, third Wilkinson power combiner 6-3, Wilkinson power divider 7, Si substrate 8, _SiO2 layer 9, total Surface waveguide 10, anchor region 11, dielectric layer 12, fixed support beam 13, cantilever beam 14, air layer 15, air bridge 16, asymmetric coplanar strip line 17, isolation resistor 18, terminal resistor 19, P-type semiconductor arm 20 , N-type semiconductor arm 21, output electrode 22, hot end 23, cold end 24, substrate film structure 25, pull-down electrode 26, first port 1-1, second port 1-2, third port 1-3, The fourth port 1-4, the fifth port 1-5, the sixth port 1-6, the seventh port 2-1, the eighth port 2-2, the ninth port 2-3, the tenth port 2-4, the Eleventh port 6-1, twelfth port 6-2, thirteenth port 6-3.

detailed description

The fixed beam indirect heating microwave signal detector of the present invention is composed of a six-port fixed beam coupler 1, a channel selection switch 2, a microwave frequency detector 3, and a microwave phase detector 4 cascaded; the six-port fixed beam coupler 1 It consists of a coplanar waveguide 10, a dielectric layer 12, an air layer 15 and a fixed beam 13; the coplanar waveguide 10 is made on the SiO ₂ layer 9, and the anchor region 11 of the fixed beam 13 is made on the coplanar waveguide 10, and the fixed beam A dielectric layer 12 is deposited under the beam 13, and forms a coupling capacitor structure together with the air layer 15 and the fixed beam 13. The length of the coplanar waveguide 10 between the two fixed beams 13 is λ/4; the channel selection switch 2 is composed of A coplanar waveguide 10, an anchor region 11, a dielectric layer 12, a cantilever beam 14, and a pull-down electrode 26 are formed; the anchor region 11 of the cantilever beam 14 is made on the coplanar waveguide 10, and the pull-down electrode 26 is made under the cantilever beam 14, and is connected with the pull-down electrode The dielectric layer 12 above the 26 together forms a switch structure; the microwave frequency detector 3 is composed of the third Wilkinson power combiner 6-3 and the sixth indirect heating microwave power sensor 5-6 in cascade; the microwave phase detector 4 is composed of the fourth indirect The heating type microwave power sensor 5-4, the fifth indirect heating type microwave power sensor 5-5, the first Wilkinson power combiner 6-1, the second Wilkinson power combiner 6-2, and the Wilkinson power divider 7 constitute; Wilkinson power The combiner and Wilkinson power divider have the same topological structure, and are composed of coplanar waveguide 10, asymmetric coplanar strip line 17, air bridge 15, and isolation resistor 18, and the signal is input from the eleventh port 6-1 as Wilkinson power divider , the signal is input from the twelfth port 6-2, and the thirteenth port 6-3 is a Wilkinson power combiner;

The first port 1-1 to the third port 1-3, the fourth port 1-4, the first port 1-1 to the fifth port 1-5, and the sixth port 1-6 of the six-port fixed beam coupler 1 The power coupling degrees are the same; the signal to be measured is input through the first port 1-1 of the six-port fixed-support beam coupler 1, and is output to the first indirect heating microwave power sensor 5-1 by the second port 1-2, and the The fourth port 1-4 and the sixth port 1-6 are output to the microwave phase detector 4, and are output to the channel selection switch 2 by the third port 1-3 and the fifth port 1-5; the seventh port of the channel selection switch 2 2-1 and the eighth port 2-2 are respectively connected to the second indirect heating microwave power sensor 5-2, the third indirect heating microwave power sensor 5-3, the ninth port 2-3 and the tenth port of the channel selection switch 2 The ports 2-4 are connected to the microwave frequency detector 3, which realizes the simultaneous detection of three microwave parameters of microwave signal power, phase, and frequency by one chip, and has the advantages of low power consumption and low cost. The detection principle of microwave power, phase and frequency can be explained as follows:

Power detection: as shown in Figure 7, the microwave power is input from the input port, and is converted into heat through the coplanar waveguide 10 input to the terminal resistor 19; the P-type semiconductor arm 20 and the N-type semiconductor arm 21 form a thermocouple, and the thermocouple is close to the terminal resistor The area 19 is used as the hot end 23, and the area near the output electrode 22 of the thermocouple is used as the cold end 24; according to the Seebeck effect, the input microwave power can be known by measuring the thermoelectric potential of the output electrode 22; the back of the hot end 23 of the thermocouple is formed by thinning the substrate Substrate thin film structure 25 to improve detection sensitivity.

Frequency detection: as shown in Figure 1, the microwave signal is output to the channel selection switch 2 through the third port 1-3 and the fifth port 1-5 of the six-port fixed beam coupler 1; the seventh port 2-5 of the channel selection switch 2 1 and the eighth port 2-2 are respectively connected to the second indirect heating microwave power sensor 5-2, the third indirect heating microwave power sensor 5-3, the ninth port 2-3 and the tenth port 2 of the channel selection switch 2 -4 is connected to the microwave frequency detector 3; the cantilever beam 14 of the channel selection switch 2 is grounded, and the pull-down electrode 26 is connected to the driving voltage. When the driving voltage is greater than or equal to the opening voltage, the cantilever beam 14 is pulled down and the channel is selected; When the seventh port 2-1 and the eighth port 2-2 of the switch 2 are selected, the output coupled powers P ₃ and P ₅ of the six-port fixed beam coupler 1 can be tested. The length of the coplanar waveguide 10 between the two fixed beams 13 of the six-port fixed beam coupler 1 is λ/4, at this time the phase difference between the third port 1-3 and the fifth port 1-5 is 90°, And as shown in formula (1), the phase difference is a linear function of frequency.

λ is the wavelength of the input microwave signal, c is the speed of light, and _εer is the equivalent dielectric constant only related to the structure. When the ninth port 2-3 and the tenth port 2-4 of the channel selection switch 2 are strobed, the two microwave signals are combined through the third Wilkinson power combiner 6-3, and the sixth indirect heating microwave The power sensor 5-6 detects the power P _s of the synthesized signal, and the frequency of the input microwave signal can be obtained according to the formula (2).

P ₃ and P ₅ are the power coupled between the third port 1-3 and the fifth port 1-5, which can be detected by the second indirect heating microwave power sensor 5-2 and the third indirect heating microwave power sensor 5-3.

Phase detector: as shown in Figure 1, the microwave signal is input to the microwave phase detector 4 through the fourth port 1-4 and the sixth port 1-6 of the six-port fixed-support beam coupler 1 for phase detection; the six-port fixed-support beam The length of the coplanar waveguide 10 between the two fixed beams 13 of the coupler 1 is λ/4, and the phase difference of the two microwave signals passing through the fourth port 1-4 and the sixth port 1-6 is 90°; Input power P _r , a reference signal with the same frequency f (measured by the microwave frequency detector 3) as the signal to be measured, the reference signal is divided into two signals with the same power and phase by the Wilkinson power divider 7, and is connected to the fourth port 1-4 and the two-way signals to be measured at the sixth port 1-6 are combined through the first Wilkinson power combiner 6-1 and the second Wilkinson power combiner 6-2; the fourth indirect heating microwave power sensor 5-4 and the second Wilkinson power combiner 6-2 Five indirect heating microwave power sensors 5-5 detect the combined power P _cs1 and P _cs2 of the left and right channels, and obtain the phase difference between the signal to be measured and the reference signal through formula (3)

P ₄ , P ₆ are the coupled powers of the fourth port 1-4 and the sixth port 1-6, and P ₄ =P ₃ , P ₆ =P ₅ .

The preparation method of the fixed beam indirect heating type microwave signal detector comprises the following steps:

1) Prepare a 4-inch high-resistance Si substrate 8 with a resistivity of 4000Ω·cm and a thickness of 400mm;

2) thermally growing a SiO ₂ layer 9 with a thickness of 1.2mm;

3) A layer of polysilicon is grown by chemical vapor deposition (CVD) with a thickness of 0.4 mm;

4) Coating a layer of photoresist and photoetching, except for the polysilicon resistance area, other areas are protected by photoresist, and phosphorus (P) ions are implanted with a doping concentration of 10 ¹⁵ cm ^-2 to form isolation resistors 18 and Terminal resistance 19;

5) Coat a layer of photoresist, and use a P ⁺ photolithography plate to perform photolithography. Except for the P-type semiconductor arm 20 area, other areas are protected by photoresist, and then boron (B) ions are implanted with a doping concentration of 10 ¹⁶ cm ^-2 , forming a P-type semiconductor arm 20 of a thermocouple;

6) Coat a layer of photoresist, and use N ⁺ photolithography plate for photolithography. Except for the N-type semiconductor arm 21 area, other areas are protected by photoresist, and then implant phosphorus (P) ions with a doping concentration of 10 ¹⁶ cm ^-2 , forming an N-type semiconductor arm 21 of a thermocouple;

7) Coating a layer of photoresist, photoetching thermopile and polysilicon resistance patterns, and then forming thermocouple arms and polysilicon resistances by dry etching;

8) Apply a layer of photoresist, and remove the photoresist at the coplanar waveguide 10, the asymmetric coplanar strip line 17, the output electrode 22 of the metal interconnection line, and the pull-down electrode 26 by photolithography;

9) Electron beam evaporation (EBE) forms the first layer of gold (Au) with a thickness of 0.3 mm, removes the photoresist and Au on the photoresist, and peels off the first layer of coplanar waveguide 10 and asymmetric coplanar strip 17. Au layer, output electrode 22, thermopile metal interconnection wire and pull-down electrode 26;

10) Deposit (LPCVD) a layer of Si ₃ N ₄ with a thickness of 0.1 mm;

11) Coating a layer of photoresist, photolithography and retaining the photoresist under the fixed support beam 13 and the cantilever beam 14, and dry etching Si ₃ N ₄ to form the dielectric layer 12;

12) Evenly coat a layer of air layer 15 and photolithographically pattern it, with a thickness of 2 mm, and keep the polyimide under the fixed support beam 13 and the cantilever beam 14 as a sacrificial layer;

13) Coating photoresist, removing the photoresist at the position of the anchor beam 13, the cantilever beam 14, the anchor region 11, the coplanar waveguide 10, the asymmetric coplanar strip line 17 and the output electrode 22 by photolithography;

14) Evaporate the seed layer of Ti/Au/Ti at 500/1500/300A°, remove the top Ti layer and then electroplate an Au layer with a thickness of 2mm;

15) removing the photoresist and the Au on the photoresist to form the fixed support beam 13, the cantilever beam 14, the anchor region 11, the coplanar waveguide 10, the asymmetric coplanar strip line 17 and the output electrode 22;

16) Deep Reactive Ion Etching (DRIE) on the back of the substrate material to make a thin film structure 25;

17) Release the polyimide sacrificial layer: soak in developer solution, remove the polyimide sacrificial layer under the fixed beam, soak in deionized water for a while, dehydrate with absolute ethanol, volatilize at room temperature, and dry in the air.

The difference between the present invention and prior art is:

The present invention adopts a novel six-port fixed beam coupling structure, which couples a part of the microwave signal transmitted in the coplanar waveguide, and uses the coupled signal to detect the power, frequency and The phase size uses an indirect heating microwave power sensor to detect the power of the microwave signal, which has good microwave characteristics and no DC power consumption; the fixed-beam indirect heating microwave signal detector of the present invention realizes the simultaneous detection of microwave signals by one chip. Detection of three microwave parameters of power, phase and frequency, with the benefits of low power consumption and low cost

A structure that satisfies the above conditions is regarded as the fixed-beam indirect heating microwave signal detector of the present invention.

Claims (3)

1. a fixed beam indirect heating type microwave signal detector is characterized in that this phase detector consists of a six-port fixed beam coupler (1), a channel selection switch (2), a microwave frequency detector (3) and a microwave The phase detectors (4) are cascaded; the power coupling degrees from the first port to the third port, the fourth port, the first port to the fifth port, and the sixth port of the six-port fixed beam coupler (1) are respectively the same , the signal to be tested is input through the first port (1-1), output to the first indirect heating microwave power detector (5-1) through the second port (1-2), and output through the fourth port (1-4) and the sixth port (1-6) are output to the first Wilkinson power combiner (6-1) and the second Wilkinson power combiner (6-2) of the microwave phase detector (4) respectively, and by the first Wilkinson power The combiner (6-1) and the second Wilkinson power combiner (6-2) are connected to the second indirect heating microwave power detector (5-2) and the third indirect heating microwave power detector (5-3); Output from the third port (1-3) and the fifth port (1-5) to the seventh port (2-1) and the eighth port (2-2) of the channel selection switch (2) of the channel selection switch (2) Connect the second indirect heating microwave power sensor (5-2) and the third indirect heating microwave power sensor (5-3), the ninth port (2-3) and the tenth port (2-3) of the channel selection switch (2) -4) connect the 3rd Wilkinson power combiner (6-3) of microwave frequency detector (3), connect the 5th indirect heating type microwave power detector (5-5) by the 3rd Wilkinson power combiner (6-3) ), thereby realizing the detection of microwave signal power, phase and frequency; Wherein, the six-port fixed-support beam coupler (1) is composed of a coplanar waveguide (10), a dielectric layer (12), an air layer (15) and a fixed-support beam (13) across the top thereof; the coplanar waveguide (10 ) is made on the SiO ₂ layer (9), the anchor region (11) is made on the coplanar waveguide (10), the dielectric layer (12) is deposited under the fixed support beam (13), and is connected with the air layer (15), solid The supporting beams (13) together form a coupling capacitor structure, and the length of the coplanar waveguide (10) between the two fixed supporting beams (13) is λ/4. 2. The fixed beam indirect heating microwave signal detector as claimed in claim 1, characterized in that the channel selection switch (2) consists of a coplanar waveguide (10), an anchor region (11), a dielectric layer (12), A cantilever beam (14) is composed of a pull-down electrode (26); the anchor region (11) of the cantilever beam (14) is made on the coplanar waveguide (10), and the pull-down electrode (26) is made under the cantilever beam (14), and is connected with The dielectric layer (12) above the pull-down electrode (26) together constitutes a switch structure; the cantilever beam (14) of the channel selection switch (2) is grounded, and the pull-down electrode (26) is connected to the driving voltage; when the driving voltage is greater than or equal to the turn-on voltage, the cantilever beam ( 14) is pulled down and the channel is gated. 3. as described in claim 1, 2, the fixed support beam indirect heating type microwave signal detector is characterized in that the indirect heating type microwave work sensor is by Si substrate (8), SiO ₂ layers (9), coplanar waveguide (10), terminal resistor (19), P-type semiconductor arm (20), N-type semiconductor arm (21), output electrode (22) constitutes; Microwave power is input to terminal resistor (19) by coplanar waveguide (10) converted into heat; the P-type semiconductor arm (20) and the N-type semiconductor arm (21) form a thermocouple; according to the Seebeck effect, the input microwave power can be known by measuring the thermoelectric potential of the output electrode (22).