Patent Description:
In recent years, terahertz wave technology, as an important research field, has attracted more and more attention at home and abroad. No matter which aspect and frequency band the terahertz wave is applied to, the reception of the terahertz wave is necessary. For the most commonly used receiver based on superheterodyne system, a mixer for frequency down conversion is a key component. In a solid-state terahertz radar and communications system, because a low-noise amplifier is difficult to implement, the mixer becomes the first stage of the receiving end, so the performance of the mixer is directly related to the performance of the entire receiver system. At the same time, since it is difficult to achieve a high-performance local oscillator in the same frequency band, sub-harmonic mixing technology is an effective way to solve this problem.

With increased requirements of system performance, requirements of receiver indexes are also increasing. To improve integration or imaging resolution, multi-channel integration of the receiver is a key issue. Because the current terahertz mixers mainly use metal cavity materials such as copper or aluminum, which can achieve a good channel spacing, multi-channel at present is still spliced by independent single channels. However, due to limitations of machining requirements of the metal cavity, it is difficult to reduce the multi-channel spacing to improve the overall integration.

<CIT> concerns a cross-bar signal mixer suitable for low-cost high-yield mass production. The mixer configuration consists of a balanced planar taper section supported upon a dielectric substrate placed across the carrier and local oscillator wave guides perpendicular to the direction of electromagnetic energy propagation. Beam lead mixer diodes are connected across the feed-point of the taper section. The local oscillator energy is injected in transverse electric mode relation at the junction of the two mixer diodes, thereby effectively decoupling the local oscillator from the carrier signal input. The intermediate frequency energy is abstracted from the same point as the local oscillator energy is injected and is decoupled by a low-pass filter. The local oscillator and the intermediate frequency circuits are incorporated on the same planar substrate as the carrier signal circuit and are therefore not critical in design.

<CIT> concerns a radio-frequency mixer and a local oscillator integrated into a single housing, and including a Gunn-type oscillator coupled to the mixer by a section of microstrip transmission line and a section of suspended stripline. A broadside coupler in the suspended stripline provides dc and intermediate-frequency isolation for the mixer, and a block of dielectric material on the microstrip provides improved temperature compensation for the diode oscillator. The entire compact assembly has good conversion loss performance over a relatively wide frequency band, and is relatively insensitive to temperature changes.

<CIT> concerns a terahertz mixer and an electronic device including the same. According to an embodiment, the terahertz mixer comprises a cavity used for respectively forming a radio frequency input waveguide and a local oscillator input waveguide and accommodating a suspended microstrip line, and steps are formed on the inner side surface of the cavity; and the suspended microstrip line is formedthrough a semiconductor growth process and is bridged on at least one part of the step, and the suspended microstrip line respectively extends into the cavities where the radio frequency input waveguide and the local oscillator input waveguide are located so as to respectively form microstrip line antennas for receiving a radio frequency input signal and a local oscillator input signal.

<CIT> concerns a transmission line substrate including a stacked body that includes insulating base materials, first and second signal lines, and first and second ground conductors. The second signal line is provided on a layer different from the layer of the first signal line and extends in parallel with the first signal line. The first ground conductor is provided on the same layer as the layer of the second signal line and overlapped with the first signal line when viewed in the Z-axis direction. The second ground conductor is provided on the same layer as the layer of the first signal line and overlapped with the second signal line when viewed in the Z-axis direction. A first transmission line includes the first signal line, the first ground conductor, and an insulating base material, and a second transmission line includes the second signal line, the second ground conductor, and the insulating base material.

The present disclosure provides a device of mixing or multiplying frequency as defined in claim <NUM> and a device of mixing or multiplying frequency as defined in claim <NUM>.

The following detailed description, for the convenience of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. Obviously, however, one or more embodiments may also be implemented without these specific details. In other cases, well-known structures and devices are shown in diagrammatic form to simplify the drawings.

According to a general inventive concept of the present disclosure, there is provided a device of mixing or multiplying frequency, including: a metal housing including a box body and a cover buckled together to define a metal cavity; and at least one frequency conversion unit including a microstrip line located in the metal cavity; and a channel structure including a radio frequency signal input channel, a local oscillator signal input channel and a signal output channel, the radio frequency signal input channel, the local oscillator signal input channel and the signal output channel pass through the metal housing and are coupled to the microstrip line respectively, wherein at least two of a plane where the radio frequency signal input channel is located, a plane where the local oscillator signal input channel is located and a plane where the signal output channel is located are not coplanar.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit.

<FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units.

As shown in <FIG>, the frequency conversion unit of the terahertz mixer includes a microstrip line <NUM> and a channel structure. The microstrip line <NUM> is located in the metal cavity. The channel structure includes a radio frequency signal input channel <NUM>, a local oscillator signal input channel <NUM> and a signal output channel, which pass through the metal housing and are coupled to the microstrip line <NUM> respectively. A part of the microstrip line <NUM> respectively extends to the metal cavity where the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> are located, so as to form an antenna <NUM> for receiving radio frequency input signals and local oscillator input signals. Other composition parts and dimension parameters of the mixer may refer to the prior art, or other documents or patents.

The specific content of this solution will be described below in combination with more specific examples. It should be understood that the dimensions and proportions in the figures are only for illustration and have nothing to do with the actual structure.

As shown in <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the mixer are respectively formed in the box body (or cover) defining the metal cavity and are parallel to the plane where the microstrip line <NUM> is located, and the signal output channel (which is an intermediate frequency signal output channel in this embodiment) is perpendicular to the plane where the microstrip line <NUM> is located and is led out from the cover or box body through an SMA connector <NUM>. The terahertz mixer changes, by using the SMA connector <NUM>, a direction along which the intermediate frequency signal of the mixer is led out, from the direction parallel to the plane where the microstrip line <NUM> is located to the direction perpendicular to the plane where the microstrip line <NUM> is located, thereby avoiding the problem of poor integration due to the presence of the radio frequency signal input channel, the local oscillator signal input channel and the signal output channel in the same plane. Moreover, it reduces the complexity and processing cost of multi-channel integration while ensuring the basic high-frequency characteristics of the mixer, which improves the flexibility of the mixer integration mode, and provides favorable conditions for further system integration.

In the embodiments shown in <FIG>, the SMA connector <NUM> is a wall-through structure and has a metal pin pointing outwards perpendicular to the principle plane. One end of the SMA connector <NUM> is level with the microstrip line <NUM> and connected to the intermediate frequency signal output port <NUM> of the microstrip line <NUM> through gold wire bonding, so as to realize a vertical led-out of the intermediate frequency signal. Those skilled in the art should understand that the SMA connector <NUM> may also adopt other connectors, such as a <NUM> connector.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units. <FIG> shows a schematic diagram of a glass insulator.

In <FIG>, the signal output channel is led out vertically through a glass insulator. Specifically, as shown in <FIG>, the glass insulator includes a metal pin <NUM> and a first columnar portion <NUM> sheathed on the middle of the metal pin <NUM>. The metal pin <NUM> points outwards perpendicular to the principle plane, with a first end being level with the microstrip line <NUM> and connected to the intermediate frequency signal output port <NUM> of the microstrip line <NUM> through gold wire bonding. The first columnar part <NUM> is made of insulating glass medium. A metal layer <NUM> is provided on an outer surface of the first columnar part <NUM>. The first columnar part <NUM> is connected to the cover or box body defining the metal housing, for example, located in a hole formed in the cover or box body.

A second end of the metal pin <NUM> of the glass insulator, which is opposite to the first end, is connected with an SMA connector so as to be connected to an external component.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units. <FIG> shows a schematic diagram of a coaxial metal column structure.

In <FIG>, the signal output channel is led out vertically through the coaxial metal column. Specifically, as shown in <FIG>, the coaxial metal column includes a metal pin <NUM> and a plurality of second columnar parts 313A, 313B, 313C, which are spaced apart from each other and sleeved on the metal pin <NUM> along the axial direction of the metal pin <NUM>. One of the second columnar parts 313A, 313B, 313C (preferably the one far away from the intermediate frequency signal output port <NUM>) is connected to the metal housing. Each of second columnar parts 313A, 313B, 313C has a metal layer <NUM> provided on its external surface The metal pin <NUM> points outwards perpendicular to the principle plane, with a first end being level with the microstrip line <NUM> and connected to the intermediate frequency signal output port <NUM> of the microstrip line through gold wire bonding.

In <FIG>, one of adjacent two of the second columnar parts 313A, 313B, 313C has a diameter difference from the other of the adjacent two of the second columnar parts 313A, 313B, 313C. The coaxial metal column adopts second columnar parts with different diameters to form effective filter characteristics, so that radio frequency signals and local oscillator signals may be filtered to ensure the output of intermediate frequency signals. Since the coaxial metal column integrates a low-pass filter, the overall length of the quartz microstrip line is shortened, thereby improving the integration of the multi-channel mixer.

A second end of the metal pin <NUM> of the coaxial metal column, which is opposite to the first end, is connected with an SMA connector so as to be connected to an external component.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit. <FIG> shows another schematic diagram of the terahertz mixer including a single frequency conversion unit shown in <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units <FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit.

<FIG> shows another schematic diagram of the terahertz mixer including a single frequency conversion unit shown in <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units.

In <FIG>, the terahertz mixer changes the intermediate signal led-out direction of the mixer, through a Rogers board <NUM>, from the direction parallel to the plane where the microstrip line <NUM> is located to the direction perpendicular to the plane where the microstrip line <NUM> is located, thereby avoiding the problem of poor integration due to the presence of the radio frequency signal input channel, the local oscillator signal input channel and the signal output channel in the same plane.

In <FIG>, the Rogers board <NUM> includes a Rogers dielectric material 413A and metal strip lines 413B located on opposite sides of the Rogers dielectric material 413A. A first end of the Rogers board <NUM> is level with the microstrip line <NUM> and connected to an intermediate frequency led-out structure <NUM> of the microstrip line <NUM> through gold wire bonding, thereby achieving vertical led-out of the intermediate frequency signal.

In <FIG>, a second end of the Rogers board <NUM> opposite to the first end is connected with an SMA connector <NUM> so as to be connected with an external component. Those skilled in the art should understand that the SMA connector <NUM> may also adopt other connectors, such as a <NUM> connector.

In <FIG>, a Rogers board <NUM>' having a high and low impedance stripline structure is employed to simultaneously serve as an intermediate frequency low pass filter, thereby filtering radio frequency local oscillator signals and allowing transmission of intermediate frequency signals.

The characteristic impedance of the Rogers board <NUM>' may include but is not limited to <NUM> ohms, so as to match the SMA connector <NUM> (or other connectors such as a <NUM> connector).

As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit are both led in perpendicularly to the length direction of the microstrip line <NUM> and are couple to the microstrip line. Those skilled in the art should understand that in some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit may also be led in along other directions. For example, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit are both led in in parallel to the length direction of the microstrip line <NUM> and are coupled to the microstrip line through a <NUM> ° turn.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit according to an exemplary embodiment of the present disclosure. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units according to yet another exemplary embodiment of the present disclosure.

In an exemplary embodiment of the present disclosure, as shown in <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit are both led in in parallel to the length direction of the microstrip line <NUM> and are couple to the microstrip line through a <NUM> ° turn. Those skilled in the art should understand that in some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit may also be led in along other directions, and the angle of the turn may also be other angles, such as <NUM> °, <NUM> ° or the like.

In an exemplary embodiment of the present disclosure, as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit are led in along opposite directions, so as to avoid interference of the radio frequency signal input channel <NUM>, the local oscillator signal input channel <NUM> and their associated components in spatial position, and also shorten the overall length of the microstrip line <NUM>, thereby improving the integration of the mixer. However, it should be noted that in some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit may also be led in along the same direction. In addition, in some other embodiments of the present disclosure, the led-in direction of the radio frequency signal input channel <NUM> may be not in parallel with the led-in direction of the local oscillator signal input channel <NUM> of the frequency conversion unit.

In an exemplary embodiment of the present disclosure, as shown in <FIG>, <FIG>, <FIG>, <FIG>, each of the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit is led in perpendicularly to the length direction of the microstrip line <NUM> and is couple to the microstrip line. In this case, when the device includes a plurality of frequency conversion units, the plurality of frequency conversion units are arranged in a row along the length direction of the microstrip line <NUM>. However, those skilled in the art should understand that in some other embodiments of the present disclosure, other arrangements may also be adopted, and the specific arrangements may be adjusted according to requirements.

In an exemplary embodiment, as shown in <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit are both led in in parallel to the length direction of the microstrip line <NUM> and are coupled to the microstrip line <NUM> through a <NUM> ° turn. In this case, if the device includes a plurality of frequency conversion units, the plurality of frequency conversion units are arranged in a row along the direction perpendicular to the length direction of the microstrip line <NUM>. However, those skilled in the art should understand that in some other embodiments of the present disclosure, other arrangements may also be adopted, and the specific arrangements may be adjusted according to requirements.

In practice, the design of the vertical led-out part of the intermediate frequency signal needs to be optimized to reduce return loss and optimize output characteristics of the intermediate frequency signal.

In an exemplary embodiment, as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> to <FIG>, the radio frequency signal input channels <NUM> in each row of frequency conversion units are parallel to each other with their ports being aligned, and the local oscillator signal input channels <NUM> are parallel to each other with their ports being aligned, so as to ensure consistence between the signal reception of the multi-channel receiver and the input local oscillator signal.

It should be noted that although in the above-mentioned embodiments, the intermediate frequency signal led-out direction of the mixer is changed, through the SMA connector or the glass insulator or the coaxial metal column or the Rogers board, from the direction parallel to the plane where the microstrip line <NUM> is located to the direction perpendicular to the plane where the microstrip line <NUM> is located, those skilled in the art should understand that in some other embodiments of the present disclosure, the intermediate frequency signal led-out direction may also be at an angle with respect to the plane where the microstrip line <NUM> is located, and the angle is not equal to zero.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit according to an exemplary embodiment of the present disclosure. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units according to another exemplary embodiment of the present disclosure. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units according to yet another exemplary embodiment of the present disclosure. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units according to yet another exemplary embodiment of the present disclosure.

As shown in <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the mixer according to the present disclosure are both led in perpendicularly to the plane where the microstrip line <NUM> is located. Here, the radio frequency signal input channel <NUM> transmits inwards perpendicular to the principle plane, the local oscillator signal input channel <NUM> transmits outwards perpendicular to the principle plane,, and the signal output channel (which is the intermediate frequency signal output channel in this embodiment) is led out in parallel to the plane where the microstrip line <NUM> is located. The terahertz mixer changes the direction where the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> are led out, from the direction parallel to the plane where the microstrip line <NUM> is located to the direction perpendicular to the plane where the microstrip line <NUM> is located, thereby avoiding the problem of poor integration due to the presence of the radio frequency signal input channel, the local oscillator signal input channel and the signal output channel in the same plane. Moreover, it reduces the complexity and processing cost of multi-channel integration while ensuring the basic high-frequency characteristics of the mixer, which improves the flexibility of the mixer integration mode and provides favorable conditions for further system integration.

In the exemplary embodiments shown in <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> are both perpendicular to the plane where the microstrip line <NUM> is located, and may be machined by means of wire cutting in the cover or box body defining the metal cavity. The SMA connector <NUM> (or other connectors such as a <NUM> connector) is a wall-through structure. Its metal pin protrudes in a direction parallel to the microstrip line <NUM>, and may be welded to the intermediate frequency output port <NUM> of the microstrip line <NUM> through conductive glue, or an intermediate frequency transition welding may be realized by using the Rogers board.

In an exemplary embodiment of the present disclosure, as shown in <FIG>, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit are led in along opposite directions, so as to avoid interference of the radio frequency signal input channel <NUM>, the local oscillator signal input channel <NUM> and their associated components in spatial position, and also shorten the overall length of the microstrip line <NUM>, thereby improving the integration of the mixer. However, it should be noted that in some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> of the frequency conversion unit may also be led in along the same direction. In addition, in some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> of the frequency conversion unit may be led in along a direction not in parallel with the direction along which the local oscillator signal input channel <NUM> of the frequency conversion unit is led in.

In an exemplary embodiment, as shown in <FIG>, if the device includes a plurality of frequency conversion units, the plurality of frequency conversion units are arranged in a row (as shown in <FIG>) or two rows (as shown in <FIG>) along a direction perpendicular to the length direction of the microstrip line <NUM>.

In an exemplary embodiment, as shown in <FIG>, the plurality of frequency conversion units are arranged in two rows along the direction perpendicular to the length direction of the microstrip line <NUM>. The frequency conversion units in the two rows are level with each other in the length direction of the microstrip line <NUM>.

In an exemplary embodiment, as shown in <FIG>, the plurality of frequency conversion units are arranged in two rows along the direction perpendicular to the length direction of the microstrip line <NUM>. The frequency conversion units in the two rows are staggered one by one in the length direction of the microstrip line <NUM>.

In an exemplary embodiment, as shown in <FIG>, the radio frequency signal input channel <NUM> has an H-surface probe transition structure, and the local oscillator signal input channel <NUM> has an H-surface probe transition structure. In practice, the design of the H-surface probe transition structure needs to be optimized to reduce the return loss and optimize the output characteristics of the intermediate frequency signal.

In an exemplary embodiment, as shown in <FIG>, the radio frequency signal input channels <NUM> in each row of frequency conversion units are parallel to each other with their ports being aligned, and the local oscillator signal input channels <NUM> are parallel to each other with their ports being aligned, so as to ensure the consistence between the signal reception of the multi-channel receiver and the input local oscillator signal.

In the exemplary embodiments shown in <FIG>, since the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> are led in perpendicularly to the plane where the microstrip line <NUM> is located, the spacing between channels is shortened and the integration is improved. In practice, the size may not be further shortened due to a large size of the connector, then a custom connector of the intermediate frequency output may be employed to achieve the purpose of small size.

The operating process of the mixer shown in <FIG> includes the following. The terahertz signal to be received passes through the radio frequency signal input channel <NUM>. In the waveguide-transition-microstrip line structure of the H-surface probe, the terahertz signal is transmitted to the antenna <NUM> of the microstrip line <NUM>. The local oscillator signal enters from the local oscillator signal input channel <NUM>, passes through a microstrip transition structure <NUM> of a duplexer and a local oscillator low-pass filter <NUM>, and is then mixed with the radio frequency signal in a gallium arsenide Schottky diode <NUM>. The radio frequency signal is mixed with second harmonic of the local oscillator. The differential intermediate frequency signal passes through an intermediate frequency filter <NUM> to the intermediate frequency signal output port <NUM>, and is then transmitted to a load through the SMA connector or other connectors such as a <NUM> connector. In order to avoid DC offset caused by the inconsistency of the pair of Schottky diodes <NUM>, a ground line <NUM> connected to the metal cavity is led out from the microstrip line <NUM>. The ground line <NUM> may be applied to the nearest metal cavity by using conductive silver glue, or may be welded to the nearest metal cavity by gold wire bonding.

<FIG> shows a schematic diagram of a terahertz mixer including a single frequency conversion unit according to another exemplary embodiment of the present disclosure. <FIG> shows a schematic diagram of a terahertz mixer including a plurality of frequency conversion units according to yet another exemplary embodiment of the present disclosure.

In an exemplary embodiment of the present disclosure, as shown in <FIG>, the radio frequency signal input channel <NUM> of the frequency conversion unit is led in in parallel to the length direction of the microstrip line and is coupled to the microstrip line through a <NUM> ° turn. The local oscillator signal input channel <NUM> of the frequency conversion unit is led in perpendicularly to the plane where the microstrip line <NUM> is located. The signal output channel is led in in parallel to the plane where the microstrip line is located. This also avoids the problem of poor integration due to the presence of the radio frequency signal input channel, the local oscillator signal input channel and the signal output channel in the same plane. Moreover, it reduces the complexity and processing cost of multi-channel integration while ensuring the basic high-frequency characteristics of the mixer, which improves the flexibility of the mixer integration mode and provides favorable conditions for further system integration.

In the exemplary embodiment shown in <FIG>, the radio frequency signal input channel <NUM> is in parallel to the length direction of the microstrip line <NUM>, the local oscillator signal input channel <NUM> is perpendicular to the plane where the microstrip line <NUM> is located, and both the radio frequency signal input channel <NUM> and the local oscillator signal input channel <NUM> may be machined by means of wire cutting in the cover or box body defining the metal cavity. The SMA connector <NUM> (or other connectors such as a <NUM> connector) is a wall-through structure. Its metal pin extends in a direction parallel to the microstrip line <NUM>, and may be welded to the intermediate frequency output port <NUM> of the microstrip line <NUM> through conductive glue, or an intermediate frequency transition welding may be realized by using the Rogers board.

Those skilled in the art should understand that in some other embodiments of the present disclosure, the local oscillator signal input channel <NUM> of the frequency conversion unit may also be led in in parallel to the length direction of the microstrip line <NUM> and be coupled to the microstrip line through a <NUM> ° turn, and the radio frequency signal input channel <NUM> of the frequency conversion unit may be led in perpendicularly to the plane where the microstrip line is located, and the signal output channel may be led out in parallel to the plane where the microstrip line <NUM> is located.

In an exemplary embodiment of the present disclosure, as shown in <FIG>, the radio frequency signal input channel <NUM> of the frequency conversion unit is led in in parallel to the length direction of the microstrip line <NUM> and is coupled to the microstrip line <NUM> through a <NUM> ° turn, so as to reduce the overall arrangement size of a single frequency conversion unit. Those skilled in the art should understand that in some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> of the frequency conversion unit may also be led in along other directions, and the angle of the turn may also be other angles, such as <NUM> °, <NUM> ° or the like.

In an exemplary embodiment, as shown in <FIG>, if the device includes a plurality of frequency conversion units, the plurality of frequency conversion units are arranged in a row along the direction perpendicular to the length direction of the microstrip line <NUM>.

In an exemplary embodiment, the radio frequency signal input channel <NUM> has an E-surface probe transition structure, and the local oscillator signal input channel <NUM> has an H-surface probe transition structure. In some other embodiments of the present disclosure, the radio frequency signal input channel <NUM> has an H-surface probe transition structure, and the local oscillator signal input channel <NUM> has an E-surface probe transition structure. In practice, the design of the probe transition structure needs to be optimized to reduce the return loss and optimize the output characteristics of the intermediate frequency signal.

The operating process of the above-mentioned mixer as shown in <FIG> includes the following. The terahertz signal that to be received passes through the radio frequency signal input channel <NUM>. In the waveguide-transition-microstrip line structure of the E-surface probe, the terahertz signal is transmitted to the antenna <NUM> of the microstrip line <NUM>. The local oscillator signal enters from the local oscillator signal input channel <NUM>, passes through a microstrip transition structure <NUM> of a duplexer and a local oscillator low-pass filter <NUM>, and then mixes with the radio frequency signal in a gallium arsenide Schottky diode <NUM>. The radio frequency signal is mixed with second harmonic of the local oscillator. The differential intermediate frequency signal passes through an intermediate frequency filter <NUM> to the intermediate frequency signal output port <NUM>, and then is transmitted to a load. In order to avoid DC offset caused by the inconsistency of the pair of Schottky diodes <NUM>, a ground line <NUM> connected to the metal cavity is led out from the microstrip line <NUM>. The ground line <NUM> may be applied to the nearest metal cavity by using conductive silver glue, or may be welded to the nearest metal cavity by gold wire bonding.

<FIG> shows a schematic diagram of a distribution of a plurality of frequency conversion units of the terahertz mixer on the box body according to another exemplary embodiment of the present disclosure. <FIG> shows a schematic diagram of a distribution of a plurality of frequency conversion units of the terahertz mixer on the cover according to another exemplary embodiment of the present disclosure.

In an exemplary embodiment, as shown in <FIG>, in case that the device includes a plurality of frequency conversion units, the plurality of frequency conversion units are divided into two groups, which are respectively arranged in the box body (see <FIG>) and the cover (see <FIG>) and arranged in mirror symmetry. Specifically, a microstrip line assembly position I of the frequency conversion unit in the cover corresponds to an air cavity position II on the microstrip line of the frequency conversion unit in the box body, and the air cavity position II on the microstrip line of the frequency conversion unit in the cover corresponds to the microstrip line assembly position I of the frequency conversion unit in the box body. In this way, the upper and lower adjacent channels have opposite intermediate frequency signal extraction directions, so as to be led out from the box body and the cover respectively, thereby reserving a large space for the SMA connector or glass insulator or coaxial metal column etc.. If the SMA connector or glass insulator or coaxial metal column etc. has the maximum outer diameter a, then it is only needed to ensure that the spacing between channels is not less than a/<NUM>. If the spacing between channels needs to be further reduced, a custom small-size connector on the intermediate frequency output port may be employed.

In an exemplary embodiment, as shown in <FIG>, the signal output channels <NUM> of each row of frequency conversion units are in parallel to each other, and two adjacent signal output channels are led out in opposite directions, so as to further reserve a large space for the SMA connector or glass insulator or coaxial metal column.

In an exemplary embodiment, as shown in <FIG>, A-A' to B'-B are marked at the corresponding positions of the box body and the cover to avoid incorrect buckling.

It should be noted that if the device includes a plurality of frequency conversion units, the plurality of frequency conversion units may be one group all arranged on the box body or all arranged on the cover.

In an exemplary embodiment, the local oscillator signal input channels <NUM> of the plurality of frequency conversion units may be collected to a port through a (one to four, or one to eight) power divider, and then input signals through the local oscillator source, so as to realize the simultaneous operation of the mixer.

It should be noted that the microstrip line <NUM> may be a quartz substrate-based microstrip line structure, or a sapphire-based microstrip line structure, or a common microstrip line structure, or a suspended microstrip line structure, or a monolithic integrated microstrip circuit of gallium arsenide (GaAs), or a monolithic integrated microstrip circuit of indium phosphide (InP). In addition, the material of the metal housing includes but is not limited to alloy metals such as aluminum or brass, and semiconductor materials based on silicon, or gallium arsenide, indium phosphide, and the like. The metal cavity defined by the metal housing may be a shielded cavity structure with a metal inner wall processed by a Micro-Electro-Mechanical System (MEMS) technology, or a shielded cavity structure with a metal inner wall processed by a micro-coaxial technology.

In addition, in an exemplary embodiment of the present disclosure, the antenna <NUM> may be integrated and processed together with the radio frequency signal input channel <NUM>. The size of the antenna <NUM> may be optimized according to the channel spacing to ensure the system's requirements for receiver parameters.

In addition, those skilled in the art should understand that the harmonic type of the mixer is not limited, and it may be a single-ended, single-balanced, double-balanced, triple-balanced, or I/Q passive mixer. The plurality of local oscillator signal input channels of the mixer may be collected to a port through a (one to four, or one to eight) power divider, and then input signals through the local oscillator source, so as to realize the simultaneous operation of the mixer.

With the terahertz mixer, at least two of a plane where the radio frequency signal input channel is located, a plane where the local oscillator signal input channel is located and a plane where the signal output channel is located are not coplanar, thereby avoiding the problem of poor integration due to the presence of the radio frequency signal input channel, the local oscillator signal input channel and the signal output channel in the same plane. Moreover, it reduces the complexity and processing cost of multi-channel integration while ensuring the basic high-frequency characteristics of the mixer, which improves the flexibility of the mixer integration mode, and provides favorable conditions for further system integration. In addition, although the foregoing embodiments are all described by taking the mixer as an example, those skilled in the art should understand that in some other embodiments of the present disclosure, the device is also applicable to a frequency multiplier.

Claim 1:
A device for mixing or multiplying frequency, comprising:
a metal housing, comprising a box body and a cover buckled together to define a metal cavity;
at least one frequency conversion unit, comprising:
a microstrip line (<NUM>) located in the metal cavity; and
a channel structure comprising a radio frequency signal input channel (<NUM>), a local oscillator signal input channel (<NUM>) and a signal output channel, the radio frequency signal input channel (<NUM>), the local oscillator signal input channel (<NUM>) and the signal output channel pass through the metal housing and are coupled to the microstrip line (<NUM>) respectively, wherein at least two of a plane where the radio frequency signal input channel (<NUM>) is located, a plane where the local oscillator signal input channel (<NUM>) is located and a plane where the signal output channel is located are not coplanar,
wherein the signal output channel is led out perpendicularly to a plane where the microstrip line (<NUM>) is located;
wherein each of the radio frequency signal input channel (<NUM>) and the local oscillator signal input channel (<NUM>) is located in a plane in parallel to the plane where the microstrip line (<NUM>) is located, characterized in that: each of the radio frequency signal input channel (<NUM>) and the local oscillator signal input channel (<NUM>) extends in a direction in parallel to a length direction of the microstrip line (<NUM>); and
wherein each of the radio frequency signal input channel (<NUM>) and the local oscillator signal input channel (<NUM>) is coupled to the microstrip line (<NUM>) through a turn.