WO2022262180A1

WO2022262180A1 - Terahertz oscillator integrated with differential antenna and field path fusion method thereof

Info

Publication number: WO2022262180A1
Application number: PCT/CN2021/129473
Authority: WO
Inventors: 胡三明; 杨佳伟; 董国庆; 沈一竹
Original assignee: 网络通信与安全紫金山实验室; 东南大学
Priority date: 2021-06-17
Filing date: 2021-11-09
Publication date: 2022-12-22
Also published as: CN113394574B; CN113394574A

Abstract

The present application discloses a terahertz oscillator integrated with a differential antenna and a field path fusion method thereof. The terahertz oscillator comprises a cross-coupling circuit and a differential substrate integrated waveguide slot antenna. The cross-coupling circuit is directly connected to the differential substrate integrated waveguide slot antenna to form an oscillation loop. A triple harmonic differential signal generated by the cross-coupling circuit is radiated by the differential substrate integrated waveguide slot antenna. The differential substrate integrated waveguide slot antenna comprises a semi-open substrate integrated waveguide cavity formed on the basis of an interdigital structure. A top metal and an underlying metal of the semi-open substrate integrated waveguide cavity are separated from each other.

Description

A Terahertz Oscillator with Integrated Differential Antenna and Its Field Circuit Fusion Method

Cross References to Related Applications

This application requires a Chinese application submitted on June 17, 2021, entitled "A Terahertz Oscillator with Integrated Differential Antenna and Its Field Circuit Fusion Method", with application number 2021106700587, the disclosure of which is incorporated herein by reference in its entirety. Applying.

technical field

The present application relates to the technical field of oscillators and antennas, in particular to a terahertz oscillator with an integrated differential antenna and a field-circuit fusion method thereof.

Background technique

The terahertz band (THz) is located between the microwave and millimeter waves and the far infrared in the electromagnetic spectrum, and the frequency range is usually 0.1-10 THz. Compared with microwave and millimeter waves, its transmission frequency bandwidth is high and its resolution is high; compared with optical bands, terahertz photons have low energy, high energy efficiency, and good penetration. Due to its unique properties due to its position in the electromagnetic spectrum, terahertz waves have great application potential in fields such as biomedicine, security inspection, high-speed communication, and nondestructive testing.

Contents of the invention

The application discloses a terahertz oscillator with an integrated differential antenna and a field-circuit fusion method thereof, and specifically discloses the following technical solutions.

A terahertz oscillator with an integrated differential antenna, the terahertz oscillator includes a cross-coupling circuit and a differential substrate integrated waveguide slot antenna; the differential substrate integrated waveguide slot antenna includes a semi-open substrate based on an interdigital structure Chip-integrated waveguide cavity, the top metal of the semi-open substrate-integrated waveguide cavity is separated from the bottom metal; wherein, the cross-coupling circuit is directly connected to the differential substrate-integrated waveguide slot antenna to form an oscillation circuit, and the three times generated by the cross-coupling circuit The harmonic differential signal is radiated through the differential substrate integrated waveguide slot antenna.

A method for field-circuit fusion of a terahertz oscillator for an integrated differential antenna, the terahertz oscillator comprising a cross-coupling circuit and a differential substrate integrated waveguide slot antenna, the method comprising: regulating the differential substrate integrated waveguide slot antenna The equivalent load impedance makes the equivalent signal source impedance of the cross-coupling circuit equivalent to the third harmonic and the equivalent load impedance of the differential substrate-integrated waveguide slot antenna conjugate matching, and the cross-coupling circuit and the differential substrate-integrated waveguide slot The antennas are directly connected to form an oscillation circuit, which is integrated into the terahertz oscillator to realize field circuit fusion.

The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the present application will be apparent from the description, drawings and claims.

Description of drawings

FIG. 1 is a structural schematic diagram of a terahertz oscillator in the present application;

Figure 2 is the equivalent circuit of the fundamental wave of the terahertz oscillator in this application;

Fig. 3 is the simplified circuit of the fundamental wave small signal of the terahertz oscillator in this application;

Figure 4 is a simplified circuit of the third harmonic small signal of the terahertz oscillator in this application;

Figure 5 shows the equivalent inductance and Q value of the differential substrate integrated waveguide slot antenna in the fundamental band;

Figure 6 is the impedance value of the differential substrate integrated waveguide slot antenna in the third harmonic band;

Fig. 7 is the radiation pattern of the differential substrate integrated waveguide slot antenna at 140 GHz;

Fig. 8 is the simulation result of the terahertz oscillator with integrated differential antenna.

detailed description

A terahertz oscillator with an integrated differential antenna and a field-circuit fusion method thereof of the present application will be further described and explained in conjunction with the accompanying drawings.

Due to the lack of effective terahertz sources and detection methods, a "terahertz gap" in the electromagnetic spectrum has formed. Terahertz band frequencies are too high for electronic devices due to high loss and low carrier velocity; on the other hand, THz band frequencies are too low for photonic devices due to the lack of sufficiently small bandgap materials.

The current terahertz system is bulky and expensive, and even requires low temperature conditions and has a fragile structure, resulting in poor reliability and short life of the terahertz system. Therefore, silicon-based platforms, especially low-cost CMOS and SiGe technologies, are becoming more and more attractive as costs and feature sizes continue to decrease. The terahertz system is fully integrated on a silicon-based platform, which can significantly reduce costs, has lower power consumption, and can work at room temperature. At the same time, silicon-based terahertz systems can also be integrated with other on-chip systems to achieve more complex functions.

Generating a terahertz signal is the first step to realize a terahertz system. Although the silicon-based manufacturing process continues to advance, the output power of the terahertz signal generated by the silicon-based process is extremely limited. The main reasons are as follows. (1) Even though the feature size of silicon-based devices keeps decreasing, the maximum oscillation frequency f _max of the transistor is only close to 300 GHz, which sets the theoretical limit that the oscillator can generate fundamental wave oscillation. When the operating frequency exceeds the f _max of the transistor, Since there is no gain in the transistor, fundamental oscillation will not occur. (2) At advanced process nodes, the thin gate oxide layer leads to low breakdown voltage, resulting in low output swing of the oscillator, which severely limits the fundamental and harmonic power. (3) The passive structure of the silicon-based process usually has a low quality factor, resulting in a large energy loss and limiting the operating frequency of the oscillator. (4) The electromagnetic coupling of the signal into the low-resistance silicon medium increases additional loss. In addition to the limited output power, there are still other challenges in the generation of terahertz signals, such as limited energy efficiency and frequency modulation bandwidth.

As the frequency rises to the terahertz band, using traditional packaging techniques (such as gold wire bonding) to interconnect the terahertz circuit with the off-chip antenna will increase the loss and uncertainty of the system and seriously deteriorate the system performance. The on-chip antenna can be directly connected to the silicon-based front-end terahertz circuit, which can eliminate the huge loss and uncertainty introduced by packaging technologies such as gold wire bonding, and reduce the difficulty of packaging. As the last stage of the transmitter, the on-chip antenna is usually designed to be connected to the front-end circuit with an impedance of 50 ohms. When the oscillator is directly connected to the on-chip antenna, the optimal load of the oscillator usually deviates from 50 ohms, and an additional matching circuit needs to be designed, resulting in emission The output power of the machine is reduced and the chip area is increased. Therefore, how to solve the problem of power transmission and impedance matching between the oscillator and the on-chip antenna, and obtain a terahertz oscillator with high output power has become a key issue in the application of terahertz technology.

Based on this, the present application integrates the differential antenna and the cross-coupling oscillator on the basis of the traditional cross-coupling oscillator to realize the integration of the differential antenna and the circuit.

As shown in Figure 1, a terahertz oscillator with an integrated differential antenna includes a cross-coupling circuit I and a differential substrate-integrated waveguide slot antenna II, wherein the cross-coupling circuit I and the differential substrate-integrated waveguide slot antenna II are directly connected to form a Oscillation circuit, the differential substrate integrated waveguide slot antenna II provides the required inductance to the cross-coupling circuit I, and provides the DC bias required by the cross-coupling circuit I, and then the cross-coupling circuit I and the differential substrate integrated waveguide slot antenna II form an oscillating circuit. That is to say, in this application, the differential substrate integrated waveguide slot antenna II is directly connected to the cross coupling circuit I to form an oscillation circuit, and the third harmonic differential signal generated by the cross coupling circuit I is radiated through the differential substrate integrated waveguide slot antenna II. The differential substrate-integrated waveguide slot antenna II includes a substrate-integrated waveguide cavity, which is a semi-open substrate-integrated waveguide cavity based on the interdigital structure 3 . The semi-open structure of the substrate-integrated waveguide cavity makes the upper and lower metals separated, that is, the top metal 31 and the bottom metal 32 are separated (not in contact), which is different from the closed structure where the upper and lower metals are connected together, and this half The open structure does not affect the performance of the antenna.

The interdigitated structure 3 includes a top metal 31, a bottom metal 32, a number of upper fingers 33 and a number of lower fingers 34, all the upper fingers 33 are connected to the top metal 31, all lower fingers 34 are connected to the bottom metal 32, and the upper The interdigitated fingers 33 and the lower interdigitated fingers 34 intersect in a comb shape, so that the upper interdigitated fingers 33 and the lower interdigitated fingers 34 are alternately arranged to form a semi-open substrate integrated waveguide cavity. Wherein, all upper fork fingers 33 are not in contact with bottom metal 32, that is, there is a gap between all upper fork fingers 33 and bottom metal 32; all lower fork fingers 34 are not in contact with top layer metal 31, that is, all There are gaps between the lower fingers 34 and the top metal 31 . The interdigitated structure 3 is beneficial for separating the DC bias and the DC ground of the circuit, and at the same time forms a semi-open substrate-integrated waveguide cavity, and the semi-open structure does not change the substrate-integrated waveguide mode.

The differential substrate integrated waveguide slot antenna II also includes a first feeder 1 , a second feeder 2 and an antenna slot 4 . The antenna slot 4 is a through slot opened in the top layer metal 31 . Only the top layer metal 31 is provided with through slots to form the antenna gap, and the bottom metal 32 is the entire metal surface, that is, the bottom metal 32 has no through slots; the first feeder 1 and the second feeder 2 are located in the semi-open substrate integrated waveguide cavity On the same side, for example, as shown in FIG. 1 , both the first feeder 1 and the second feeder 2 are located on the side of the semi-open substrate integrated waveguide cavity close to the cross-coupling circuit I. One end of each of the first feeder 1 and the second feeder 2 is connected to the top layer metal 31, and the other end is extended outside the semi-open substrate integrated waveguide cavity for connecting the cross-coupling circuit I. In addition, feeder slots 11 are provided on the outer peripheries of the first feeder 1 and the second feeder 2 .

In some embodiments, there is only one antenna slot 4, which is set at the center of the semi-open substrate integrated waveguide cavity.

In order to realize the function of a differential antenna, the first feeder 1 and the second feeder 2 are configured as differential feeders, and are symmetrically distributed on both sides of the antenna slot 4 . The existing third harmonic can easily exceed the maximum oscillating frequency f _max of the transistor, and the fundamental wave cannot oscillate when it exceeds f _max , but the use of differential antennas to radiate the third harmonic breaks through the limitation of the output frequency of the oscillator. The third harmonic radiation of the differential antenna breaks through the limitation of the maximum oscillation frequency of the silicon-based CMOS process on the output frequency of the oscillator, and the differential structure is conducive to improving the phase noise of the oscillator.

In addition, the differential substrate integrated waveguide slot antenna II also includes a virtual ground terminal 5, which is set on the top metal 31, and the virtual ground terminal 5 is connected to the DC bias VDD; the bottom metal 32 is grounded.

The first feeder 1 and the second feeder 2 are only connected to the top layer metal 31, and it is necessary to provide DC bias VDD to the drains of the first field effect transistor Q1 and the second field effect transistor Q2, and the first field effect transistor Q1 and the second field effect transistor Q1 The effect transistor Q2 is respectively connected through the first feeder 1, the second feeder 2 and the virtual ground terminal 5 of the top metal 31, and provides a DC bias VDD at the virtual ground 5, while the bottom metal 32 is connected to the DC ground GND, due to the interdigitated structure The top-layer metal 31 and the bottom-layer metal 32 are separated from each other, so that the DC bias VDD and the DC ground GND will not be short-circuited.

The cross-coupling circuit I includes a first field effect transistor Q1, a second field effect transistor Q2, a first inductor L1 and a second inductor L2, the sources of the first field effect transistor Q1 and the second field effect transistor Q2 are grounded, and the first field effect transistor The drain of the effect transistor Q1 is connected to the gate of the second field effect transistor Q2 through the first inductance L1, and the drain of the second field effect transistor Q2 is connected to the gate of the first field effect transistor Q1 through the second inductor L2. The drains of the field effect transistor Q1 and the second field effect transistor Q2 output the third harmonic differential signal. The first feeder 1 and the second feeder 2 are connected to the drains of the first field effect transistor Q1 and the second field effect transistor Q2 respectively.

The cross-coupling connection of the first field effect transistor Q1, the second field effect transistor Q2, the first inductor L1 and the second inductor L2 enhances the equivalent negative conductance of the cross-coupled oscillator. In the terahertz band, the parasitic capacitance of the transistor is usually used as the capacitance required by the oscillator, and the inductance required by the oscillator is provided by the differential substrate integrated waveguide slot antenna II, that is, in the circuit structure, the differential substrate integrated waveguide slot antenna II is at the fundamental wave In the band, it is equivalent to an inductance.

The differential substrate integrated waveguide slot antenna II has a triple role: providing the inductance required for the cross-coupling circuit, an antenna that radiates the third harmonic, and providing the DC bias required for the cross-coupling circuit. That is to say, this application directly connects the differential substrate integrated waveguide slot antenna and the cross-coupling circuit to form an oscillation circuit, and then integrates them together. The differential substrate integrated waveguide slot antenna is used as the inductance, third harmonic The wave radiation antenna and the DC bias simultaneously as the cross-coupling circuit do not require a matching circuit between the differential substrate integrated waveguide slot antenna and the cross-coupling circuit. The DC bias of the cross-coupled circuit refers to the bias voltage required by the field effect transistor of the circuit.

The same-side feeding characteristics of the differential antenna enable the substrate-integrated waveguide slot antenna to be directly connected to the cross-coupling circuit, which has a compact structure, avoids the introduction of additional inductance, realizes the matching of the oscillation frequency and the antenna radiation frequency, and realizes the optimal load of the third harmonic at the same time, making The third harmonic output power is maximized for transfer to the differential antenna. The application is realized by using a standard CMOS process, which has the advantages of high integration and low cost.

A field-path fusion method for a terahertz oscillator with an integrated differential antenna. The terahertz oscillator includes a cross-coupling circuit I and a differential substrate integrated waveguide slot antenna II. Exemplarily, the terahertz Hertzian oscillators are exemplified by the differential antenna-integrated terahertz oscillators described above with reference to FIGS. 1-4. The method includes: by controlling the conjugate matching of the equivalent signal source impedance of the cross-coupling circuit I at the third harmonic equivalent and the equivalent load impedance of the substrate-integrated waveguide slot antenna II, the cross-coupling circuit I and the substrate-integrated waveguide slot Antenna II is directly connected to form an oscillation circuit and integrated into a terahertz oscillator to realize field-circuit fusion. Field-circuit fusion refers to the fusion of electromagnetic fields and circuits. Through simulation design and verification, the differential antenna is designed based on electromagnetic fields, and the oscillator is based on circuit design. A terahertz oscillator with an integrated differential antenna in this application includes both electromagnetic field simulation and circuit simulation, that is, the terahertz oscillator is integrated through electromagnetic field design and circuit design at the same time. Conjugate matching can improve the output power of the cross-coupling circuit Ⅰ, and make the cross-coupling circuit Ⅰ and the substrate-integrated waveguide slot antenna Ⅱ directly connected without impedance matching network.

The field-circuit fusion method in this application is not limited to this specific design, and can be extended to related fields of other passive devices and active circuits.

The following is the principle of field road fusion:

The equivalent circuit of the terahertz oscillator at the fundamental wave is shown in Figure 2. The differential substrate integrated waveguide slot antenna II is equivalent to the differential first inductance L3 and the differential second inductance L4 in the fundamental wave band, where the differential first inductance The values of L3 and differential second inductance L4 are related to the size of the semi-open substrate integrated waveguide cavity, the length and width of the first feeder 1 and the second feeder 2, and the size and position of the feeder gap 11, which can be determined by The simulation calculates the specific numerical value. The equivalent circuit constitutes a cross-coupled oscillator. The simplified model of its small-signal equivalent circuit is shown in Fig. 3. The cross-coupled circuit is equivalent to the parallel connection of the negative conduction G _m and the parasitic capacitance C _eq . The size of the transistor in the cross-coupled circuit determines the negative Conduction and parasitic capacitance, the larger the negative conduction is, the higher the output power is, and the parasitic capacitance and equivalent inductance determine the oscillation frequency.

The differential substrate integrated waveguide slot antenna is equivalent to the parallel connection of inductance L _T and conductance G _T , and the cross-coupled oscillator needs to satisfy G _m >G _T to start oscillation. In order to ensure higher output power, the negative conductance should be as large as possible, and the inductance The conductance should be as small as possible, that is, high-Q inductance is required. The first inductance L1 and the second inductance L2 can enhance the negative conductance of the cross-coupling circuit. The fundamental frequency is determined by the parasitic capacitance C _eq in the oscillation circuit and the equivalent inductance L _T Determine, select the appropriate transistor size and the value of the fundamental equivalent inductance of the differential substrate integrated waveguide slot antenna, the drain of the transistor generates a differential fundamental signal, and at the same time, there are harmonics in the drain output of the transistor due to the nonlinearity of the transistor Signal.

The simplified circuit of the terahertz oscillator with integrated differential antenna at the third harmonic is shown in Figure 4. The cross-coupled oscillator at the third harmonic is equivalent to a third harmonic signal current source I _3f and the equivalent signal source impedance Z _S , the differential substrate integrated waveguide slot antenna is equivalent to the load impedance Z _Load , when the load impedance and the source impedance are conjugate matched, that is, Z _Load = Z _S *, the third harmonic signal is input to the differential substrate integrated waveguide slot antenna Maximum energy to achieve optimal power matching. The equivalent signal source impedance is the impedance presented by the cross-coupling circuit at the third harmonic, which is determined by the first FET, the second FET, the first inductance and the second inductance, but these parameters have been determined in the fundamental frequency oscillation circuit , in conjugate matching, only the corresponding load impedance Z _Load can be designed to obtain the maximum output power. The equivalent load impedance Z _Load of the substrate-integrated waveguide slot antenna II is determined by the size of the semi-open substrate-integrated waveguide cavity, the first The length and width of the feeder 1 and the second feeder 2, the size and position of the feeder slot 11 are regulated, and the load impedance is adjusted according to the third harmonic source impedance of the cross-coupled circuit to optimize the structural parameters of the differential substrate integrated waveguide slot antenna, so that The equivalent load impedance and source impedance of the antenna can achieve conjugate matching. The structural parameters here include the size of the semi-open substrate integrated waveguide cavity, the length and width of the first feeder 1 and the second feeder 2, and the size of the feeder slot 11. size and location.

Example:

In this embodiment, both the first field effect transistor Q1 and the second field effect transistor Q2 are NMOS transistors, based on a 0.18 μm CMOS process, and the maximum oscillation frequency is about 70 GHz. The above circuit structure is simulated and optimized, the sizes of the first FET and the second FET are selected, and the equivalent negative conduction G _m and parasitic capacitance C _eq of the cross-coupling circuit are fixed.

Figure 5 shows the equivalent inductance and Q value of the differential substrate integrated waveguide slot antenna in the fundamental band. At 47GHz, the differential substrate integrated waveguide slot antenna presents a differential inductance with a Q value of 12.5 and an inductance of 30.7pH. Figure 6 shows the impedance value of the differential substrate integrated waveguide slot antenna in the third harmonic band. At 140 GHz, the differential substrate integrated waveguide slot antenna presents a load with an impedance value of 24-j11. Figure 7 shows the radiation pattern of the differential substrate integrated waveguide slot antenna at 140GHz, which shows that the differential substrate integrated waveguide slot antenna has a -3.5dBi gain at 140GHz. Figure 8 shows the simulation results of the terahertz oscillator with integrated differential antenna, which shows that the terahertz oscillator with integrated differential antenna can generate 140GHz signal, the output power is -18dBm, and the equivalent isotropic radiated power EIRP of the transmitter is -21.5 dBm.

In summary, the terahertz oscillator with integrated differential antenna and the field-circuit fusion method provided by the present application have the following beneficial effects.

1. This application integrates the differential substrate-integrated waveguide slot antenna and the cross-coupling circuit together, and the differential substrate-integrated waveguide slot antenna is used as the inductance required by the oscillation circuit formed by the two, the third harmonic radiation antenna and the cross-coupling circuit at the same time DC bias without differential substrate integrated waveguide slot antenna and cross-coupling circuit between the matching circuit;

2. The third harmonic radiation of the differential antenna breaks through the limitation of the maximum oscillation frequency of the silicon-based CMOS process on the output frequency of the oscillator, and the differential structure is conducive to improving the phase noise of the oscillator;

3. The interdigitated structure is conducive to separating the DC bias and DC ground of the circuit, and at the same time forms a semi-open substrate integrated waveguide cavity, and the semi-open structure does not change the substrate integrated waveguide mode;

4. The same-side feeding characteristics of the differential antenna enable the differential substrate integrated waveguide slot antenna to be directly connected to the cross-coupling circuit, with a compact structure, avoiding the introduction of additional inductance, matching the oscillation frequency with the antenna radiation frequency, and achieving the optimal third harmonic load, so that the third harmonic output power is maximized and transmitted to the differential antenna;

5. This application is realized by standard CMOS technology, which has the advantages of high integration and low cost.

The above are only preferred embodiments of the present application, and it should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the principle of the application, and these improvements and modifications should also be considered For the scope of protection of this application.

Claims

A terahertz oscillator with an integrated differential antenna, comprising:

cross-coupling circuits; and

A differential substrate-integrated waveguide slot antenna, the differential substrate-integrated waveguide slot antenna includes a semi-open substrate-integrated waveguide cavity based on an interdigital structure, and the top layer metal and bottom layer of the semi-open substrate-integrated waveguide cavity metal separation;

Wherein, the cross-coupling circuit is directly connected to the differential substrate-integrated waveguide slot antenna to form an oscillation loop, and the third harmonic differential signal generated by the cross-coupling circuit is radiated through the differential substrate-integrated waveguide slot antenna.
The terahertz oscillator with an integrated differential antenna according to claim 1, wherein: the interdigital structure includes a top metal, a bottom metal, several upper interdigits and several lower interdigits, and all the upper interdigits and the top metal All the lower fingers are connected to the underlying metal, and the upper fingers and the lower fingers are intersected and alternately arranged to form the semi-open substrate integrated waveguide cavity.
The terahertz oscillator with integrated differential antenna according to claim 2, wherein: there are gaps between all the upper fingers and the bottom metal, and there are gaps between all the lower fingers and the top metal There is a gap in between.
The terahertz oscillator with integrated differential antenna according to claim 2, wherein: said differential substrate integrated waveguide slot antenna further comprises a first feeder line, a second feeder line, and an antenna slot, and said antenna slot is opened on the top layer metal through slots; the first feeder and the second feeder are formed as differential feeders, and are located on the same side of the semi-open substrate integrated waveguide cavity, each of the first feeder and the second feeder One end is connected to the top layer metal, and the other end is extended to the outside of the semi-open substrate integrated waveguide cavity for connecting the cross-coupling circuit.
The terahertz oscillator integrated with a differential antenna according to claim 4, wherein: feeder slots are provided on outer peripheries of the first feeder and the second feeder.
The terahertz oscillator with integrated differential antenna according to claim 4, wherein there is only one antenna slot, which is arranged in the center of the semi-open substrate integrated waveguide cavity.
The terahertz oscillator with integrated differential antenna according to claim 6, wherein: the first feeder and the second feeder are symmetrically distributed on both sides of the antenna slot.
The terahertz oscillator with integrated differential antenna according to claim 4, wherein: the top layer metal is provided with a virtual ground terminal, and the virtual ground terminal is connected to a DC bias VDD; the bottom layer metal is grounded.
The terahertz oscillator with integrated differential antenna according to claim 1, wherein: the cross-coupling circuit includes a first field effect transistor, a second field effect transistor, a first inductor, and a second inductor, and the first field effect The sources of the transistor and the second field effect transistor are grounded, the drain of the first field effect transistor is connected to the gate of the second field effect transistor through the first inductance, and the drain of the second field effect transistor is connected to the first field effect transistor through the second inductor. The gate of the field effect transistor is connected, and the drains of the first field effect transistor and the second field effect transistor output a third harmonic differential signal.
The terahertz oscillator with integrated differential antenna according to claim 8, wherein: the cross-coupling circuit includes a first field effect transistor and a second field effect transistor, and the first field effect transistor and the second field effect transistor The drains of the tubes are respectively connected to the first feeder and the second feeder so as to be connected to the virtual ground terminal of the top layer metal.
The terahertz oscillator with integrated differential antenna according to claim 1, wherein: the equivalent signal source impedance of the cross-coupling circuit at the third harmonic is equivalent to the equivalent load impedance of the differential substrate integrated waveguide slot antenna Conjugate matching.
A method for field-circuit fusion of a terahertz oscillator for an integrated differential antenna, the terahertz oscillator includes a cross-coupling circuit and a differential substrate integrated waveguide slot antenna, wherein the method includes: regulating the differential substrate integrated waveguide The equivalent load impedance of the slot antenna makes the equivalent signal source impedance of the cross-coupling circuit equivalent to the third harmonic and the equivalent load impedance of the differential substrate integrated waveguide slot antenna conjugate matching, and the cross-coupling circuit and the differential base The chip integrated waveguide slot antenna is directly connected to form an oscillation circuit, and integrated into the terahertz oscillator to realize field circuit fusion.
The field-circuit fusion method for a terahertz oscillator for an integrated differential antenna according to claim 12, wherein: the differential substrate-integrated waveguide slot antenna includes a semi-open substrate-integrated waveguide cavity; The equivalent load impedance of the chip-integrated waveguide slot antenna includes: adjusting the size of the semi-open substrate-integrated waveguide cavity.
The field-circuit fusion method for a terahertz oscillator with an integrated differential antenna according to claim 13, wherein: a first feeder and a second feeder are provided on the same side of the semi-open substrate integrated waveguide cavity; The regulation of the equivalent load impedance of the differential substrate integrated waveguide slot antenna also includes: adjusting the length and width of the first feeder and the second feeder.
The field-circuit fusion method for a terahertz oscillator for an integrated differential antenna according to claim 14, wherein: the outer circumference of the first feeder and the second feeder is provided with a feeder gap; the control differential substrate integrated The equivalent load impedance of the waveguide slot antenna also includes: adjusting the size and position of the feeder slot.
The field-circuit fusion method for a terahertz oscillator with an integrated differential antenna according to claim 13, wherein the semi-open substrate-integrated waveguide cavity includes an interdigitated structure, and the semi-open substrate-integrated waveguide The top metal of the cavity is separated from the bottom metal.
The field-circuit fusion method for a terahertz oscillator with an integrated differential antenna according to claim 16, wherein the interdigital structure includes a top layer metal, a bottom layer metal, several upper fingers and several lower fingers, all of which The upper fingers are connected to the top metal, all the lower fingers are connected to the bottom metal, and the upper fingers and the lower fingers are intersected and alternately arranged to form the semi-open substrate integrated waveguide cavity.