Patent Description:
With rapid growth of traffic in a network data center, a requirement for a transmission rate between devices in the data center is increasingly high, and a large quantity of high-speed cables are required for interconnection between cabinets in the data center and inside the cabinets. Currently, one connection mode is using a direct attach copper cable. However, as operating frequency increases, an increased metal loss greatly limits a transmission distance and a transmission rate of the copper cable. Another connection mode is using an active optical cable. However, because optical-to-electrical conversion is required for transmitting and receiving, power consumption and costs are greatly increased.

Currently, there is still another interconnection mode, that is, using a terahertz (THz) frequency band as a carrier, and using a terahertz transmission line as a transmission medium, to perform interconnection in the data center and another short-distance high-speed communication scenario. At an interface between the terahertz transmission line and a communication device, a terahertz signal in a radio frequency transceiver chip is usually guided into a resonant cavity of a metal connector through a microstrip, and an electromagnetic signal is coupled to the terahertz transmission line. This type of connector introduces a reflection resonance point. As a result, coupling efficiency and operating bandwidth are greatly reduced.

Document <CIT> discloses a dielectric transmission line coupler, comprising a circuit board, a microstrip line, a metal connector, and a coupling part.

Embodiments of the present invention provide a terahertz carrier sending apparatus and a terahertz carrier receiving apparatus, to implement efficient electromagnetic coupling and improve data transmission bandwidth.

According to a first aspect, an embodiment of the present invention provides a terahertz carrier sending apparatus, including a feed transmission line, a mode excitation structure, a mode conversion structure, a terahertz transmission line, and a circuit board. The feed transmission line is configured to: receive an electrical signal sent by a radio frequency sending circuit, and transmit the electrical signal to the mode excitation structure. The mode excitation structure is configured to excite a terahertz signal based on the received electrical signal. The mode conversion structure includes an inner cavity whose inner wall is metal, and the mode excitation structure and one end of the terahertz transmission line are located in the inner cavity, so that the terahertz signal excited by the mode excitation structure is coupled into the terahertz transmission line. The terahertz transmission line is configured to transmit the terahertz signal. The circuit board is configured to fasten the feed transmission line and the mode excitation structure, the mode conversion structure further includes a positioning slot, configured to insert a part of the circuit board and the mode excitation structure into the inner cavity of the mode conversion structure. A plurality of metal through holes are distributed on both sides of the mode excitation structure. A boundary of the positioning slot is metal and press-fitted on the metal through holes on the both sides of the mode excitation structure. In this way, efficient electromagnetic coupling is implemented, and data transmission bandwidth is improved.

In a possible design, the feed transmission line, the mode excitation structure, and the metal through hole are located on the circuit board. Therefore, coupling efficiency can be further improved.

In still another possible design, the feed transmission line, the mode excitation structure, and the metal through hole are located on a package substrate of a radio frequency sending chip, and a metal through hole part on the package substrate and a corresponding part of the PCB board are press-fitted by the boundary of the positioning slot. Therefore, coupling efficiency can be further improved.

In still another possible design, the feed transmission line, the mode excitation structure, and the metal through hole are located on a radio frequency sending chip, and a metal through hole part on the chip and a corresponding part of the PCB board are press-fitted by the boundary of the positioning slot. Therefore, coupling efficiency can be further improved.

In still another possible design, the radio frequency sending chip further includes an impedance matching structure, configured to match impedance between the feed transmission line and the mode excitation structure. Therefore, coupling efficiency can be further improved.

In still another possible design, a plurality of metal through holes are distributed on both sides of the impedance matching structure. Therefore, coupling efficiency can be further improved.

In still another possible design, the impedance matching structure includes a uniform substrate integrated waveguide and a tapered substrate integrated waveguide, and distances between metal through holes on both sides of the tapered substrate integrated waveguide also gradually change accordingly. Therefore, coupling efficiency can be further improved.

In still another possible design, a radiation phase center of the mode conversion excitation structure coincides with an axial direction of the mode conversion structure. Therefore, coupling efficiency can be further improved.

According to a second aspect, an embodiment of the present invention provides a terahertz carrier receiving apparatus, including a terahertz transmission line, a mode conversion structure, a mode excitation structure, a feed transmission line, and a circuit board. The terahertz transmission line is configured to receive a terahertz signal. The mode conversion structure includes an inner cavity whose inner wall is metal, and the mode excitation structure and one end of the terahertz transmission line are located in the inner cavity, so that the terahertz signal in the terahertz transmission line is coupled into the mode excitation structure. The mode excitation structure is configured to: convert the terahertz signal into an electrical signal, and send the electrical signal to the feed transmission line. The feed transmission line is configured to transmit the electrical signal to a radio frequency receiving circuit. The circuit board is configured to fasten the feed transmission line and the mode excitation structure. The mode conversion structure further includes a positioning slot, configured to insert a part of the circuit board and the mode excitation structure into the inner cavity of the mode conversion structure. A plurality of metal through holes are distributed on both sides of the mode excitation structure. A boundary of the positioning slot is metal and press-fitted on the metal through holes on the both sides of the mode excitation structure. In this way, efficient electromagnetic coupling is implemented, and data transmission bandwidth is improved.

In still another possible design, the feed transmission line, the mode excitation structure, and the metal through hole are located on the circuit board. Therefore, coupling efficiency can be further improved.

In still another possible design, the feed transmission line, the mode excitation structure, and the metal through hole are located on a package substrate of a radio frequency receiving chip, and a metal through hole part on the package substrate and a corresponding part of the PCB board are press-fitted by the boundary of the positioning slot. Therefore, coupling efficiency can be further improved.

In still another possible design, the feed transmission line, the mode excitation structure, and the metal through hole are located on a radio frequency receiving chip, and a metal through hole part on the chip and a corresponding part of the PCB board are press-fitted by the boundary of the positioning slot. Therefore, coupling efficiency can be further improved.

In still another possible design, the radio frequency receiving chip further includes an impedance matching structure, configured to match impedance between the feed transmission line and the mode excitation structure. Therefore, coupling efficiency can be further improved.

To make objectives, technical solutions, and advantages of the present invention clearer, the following further describes implementations of the present invention in detail with reference to accompanying drawings.

A terahertz carrier sending apparatus and a terahertz carrier receiving apparatus provided in embodiments of the present invention may be used in a high-speed interconnection scenario, for example, a data center. As shown in <FIG>, a terahertz carrier sending and receiving apparatus <NUM> (which may also be referred to as a terahertz cable) may be used for data transmission between devices in the data center. For example, the terahertz carrier sending and receiving apparatus <NUM> may be used between each service device <NUM> in a cabinet and a cabinet top switch <NUM>, between the service device <NUM> and a cabinet top switch <NUM> in another cabinet, or between the cabinet top switch <NUM> and a convergence LAN switch <NUM>.

<FIG> is a schematic diagram of a structure of a terahertz carrier sending and receiving apparatus according to an embodiment of the present invention. The apparatus includes a housing packaging structure <NUM>, and a printed circuit board (PCB) <NUM> is packaged in the housing packaging structure. A baseband signal processing chip <NUM>, a radio frequency sending chip <NUM>, and a radio frequency receiving chip <NUM> are installed on the PCB board. An electromagnetic coupling structure mode conversion structure <NUM> is further packaged in the housing packaging structure <NUM>, and is connected to the radio frequency sending chip <NUM>, the radio frequency receiving chip <NUM>, and a terahertz transmission line <NUM>.

When a message is sent, a to-be-sent service signal enters the radio frequency sending chip <NUM> after being processed by the baseband signal processing chip <NUM>, and the electromagnetic coupling structure <NUM> is configured to couple, to the terahertz transmission line <NUM> for sending, a carrier signal output by the radio frequency sending chip <NUM>. In addition, when a message is received, the electromagnetic coupling structure <NUM> couples, to the radio frequency receiving chip <NUM>, a carrier signal received through the terahertz transmission line <NUM>, and the baseband signal processing chip <NUM> processes the carrier signal to obtain a service signal. The electromagnetic coupling structure generally includes a feed transmission line, a mode excitation structure, and a mode conversion structure. A coupling structure may be implemented on a PCB board, may be directly coupled on a chip, or may be coupled on a package structure of a chip.

The baseband signal processing chip <NUM>, the radio frequency sending chip <NUM>, and the radio frequency receiving chip <NUM> may also be packaged in a service device. Alternatively, the radio frequency sending chip <NUM> and the radio frequency receiving chip <NUM> may be integrated into one chip for implementation. Bidirectional transmission and reception may also be implemented by using one terahertz transmission line <NUM>. To be specific, two different terahertz frequencies are used to carry terahertz signal transmission in two directions. In this case, one mode conversion structure <NUM> may be configured for bidirectional coupling, and may not only couple a to-be-sent carrier signal into a terahertz transmission line, but also couple a carrier signal received through the terahertz transmission line into a radio frequency receiving chip.

<FIG> is a schematic diagram of a structure of a terahertz carrier transceiver apparatus according to an embodiment of the present invention. Both a feed transmission line and a mode excitation structure are packaged on a PCB board <NUM>, and an electromagnetic signal in a radio frequency transceiver chip is guided to the PCB board in a chip packaging manner such as bonding (bonding wire) or flip (flip chip). The apparatus shown in <FIG> includes the following parts:.

A carrier signal of a radio frequency sending chip <NUM> is fed into a uniform substrate integrated waveguide <NUM> through a feed microstrip <NUM> with a tapered structure, to convert from a quasi-TEM mode of a carrier signal in a plane feed microstrip structure to a quasi-TE<NUM> mode of a carrier signal in the uniform substrate integrated waveguide. Further, the uniform substrate integrated waveguide <NUM> is connected to a tapered substrate integrated waveguide <NUM> for better impedance matching with a mode excitation structure <NUM>. The mode excitation structure <NUM> in <FIG> is a forward and reverse linearly tapered slot end-fire antenna.

An inner cavity of a mode conversion structure <NUM> is cylindrical, an inner wall of the mode conversion structure <NUM> is metal, an eccentric position at one end of the mode conversion structure <NUM> is provided with a rectangular positioning slot <NUM>, and the other end of the mode conversion structure <NUM> may be inserted into a terahertz transmission line <NUM>. The PCB board <NUM> is inserted into the positioning slot <NUM>, so that a carrier signal sent by the end-fire antenna may be coupled into the terahertz transmission line <NUM> that is inserted into the inner cavity of the mode conversion structure <NUM>.

Metal through holes <NUM> are arranged on both sides of the substrate integrated waveguide <NUM>/<NUM> and the end-fire antenna <NUM>. In this way, when the PCB board is inserted into the positioning slot, a boundary of the positioning slot is press-fitted by the metal through holes. Because the boundary of the positioning slot <NUM> also uses a metal material, cavity leakage of an electromagnetic wave in the mode conversion structure <NUM> is reduced, and efficiency of coupling an electromagnetic signal from the end-fire antenna to the terahertz transmission line is improved. The tapered substrate integrated waveguide is used for feeding, to improve a broadband range of impedance matching.

Some related dimensions of a feed tapered section, the metal through hole, the positioning slot need to satisfy related conditions, to better implement carrier signal coupling. Refer to <FIG>. The related dimensions and conditions to be satisfied are described below.

A feed tapered section of a tapered slot end-fire antenna needs to satisfy: <MAT>.

Parameters in the formula <NUM> include a width Ws between through holes of a substrate integrated waveguide at a feed tapered section, a width Wu between through holes of the substrate integrated waveguide at a uniform section, a quantity N of metal through holes at the tapered section, a tapered distance iy of tapered metal through holes, a length Tl of the substrate integrated waveguide at the feed tapered section, a metal through hole diameter d, and a metal through hole spacing iz.

A tapered slot end-fire antenna and metal through holes on both sides of the tapered slot end-fire antenna need to satisfy: <MAT>.

Parameters in the formula <NUM> include a bottom patch width Wl of the forward and reverse linearly tapered slot antenna, a width Ws between through holes of the substrate integrated waveguide at the feed tapered section, a length L of the forward and reverse linearly tapered slot antenna, a quantity M of metal through holes arranged on both sides of the forward and reverse linearly tapered slot antenna, a metal through hole diameter d, and a metal through hole spacing iz.

A position relationship between a metal mode converter and the PCB needs to satisfy: <MAT>.

Parameters in the formula <NUM> include a slot height Ct of the metal mode converter, a thickness St of a middle layer of the PCB board, a thickness Mt between an upper metal layer and a lower metal layer of the PCB board, a slot depth Cl of the metal mode converter, and a length L of the forward and reverse linearly tapered slot antenna.

According to embodiments of the present invention, leakage of an electromagnetic wave in the mode conversion structure is reduced, and efficiency of coupling an electromagnetic signal from the end-fire antenna to the terahertz transmission line is improved. For example, coupling efficiency may be learned from a diagram of electric field mode distribution of electromagnetic simulation. Specifically, simulation is performed based on embodiments shown in <FIG>, and a solid core terahertz transmission line whose circular cross-sectional diameter is <NUM> and that is made from polytetrafluoroethylene is selected. Related dimensions include a diameter Cd = <NUM>, a width Wu = <NUM> between through holes of the substrate integrated waveguide at the uniform section, a width Ws = <NUM> between through holes of the substrate integrated waveguide at the feed tapered section, a length Tl = <NUM> of the substrate integrated waveguide at the feed tapered section, a metal through hole diameter d = <NUM>, a metal through hole spacing iz = <NUM>, a tapered distance iy = <NUM> of tapered metal through holes, a length L = <NUM> of a forward and reverse linearly tapered slot antenna, a bottom patch width Wl = <NUM> of the forward and reverse linearly tapered slot antenna, a quantity N = <NUM> of metal through holes at the tapered section, a quantity M = <NUM> of metal through holes arranged on both sides of the forward and reverse linearly tapered slot antenna, a thickness St = <NUM> of the middle layer of the PCB board, a thickness Mt = <NUM> between the upper metal layer and the lower metal layer of the PCB board, a slot height Ct = <NUM> of the metal mode converter, and a slot depth Cl = <NUM> of the metal mode converter.

According to the foregoing related dimensions, a schematic diagram of electric field mode distribution shown in <FIG> may be obtained through electromagnetic simulation. An electromagnetic signal is connected from the microstrip <NUM> on the PCB board to the on-chip substrate integrated waveguide <NUM>, to convert from a quasi-TEM mode to a quasi-TE<NUM> mode. Then, the electromagnetic signal feeds, through the substrate integrated waveguide <NUM> on the PCB board, the forward and reverse linearly tapered slot mode excitation structure <NUM> whose both sides are arranged with metal through holes, to excite a transmission fundamental mode TE<NUM> mode in the circular metal mode conversion structure <NUM>. Then, an electromagnetic wave is coupled into the solid core terahertz transmission line <NUM> with a tapered end face through the mode conversion structure <NUM>, to implement fundamental mode transmission of an HE<NUM> mode. From the electric field mode distribution, it may be learned that efficient mode field conversion of the electromagnetic signal from the radio frequency transceiver chip to the terahertz transmission line may be implemented by using the mode conversion structure on the PCB board.

As shown in <FIG>, through electromagnetic simulation, it may be further learned that a transmission parameter from the feed microstrip on the PCB to the solid core terahertz transmission line is greater than -<NUM> dB in a frequency range of <NUM> to <NUM>, and a scattering parameter is less than -<NUM> dB. This indicates that coupling efficiency is high in a very wide frequency band from the radio frequency transceiver chip to the terahertz transmission line. This helps improve a transmission distance and a communication rate of a system.

As shown in <FIG>, an embodiment of the present invention further provides another terahertz carrier transceiver apparatus. In the figure, a mode conversion structure <NUM> whose inner cavity has a rectangular cross section is used in the apparatus, and is connected to a cylindrical waveguide <NUM> through a segment of a square-circular conversion structure <NUM>. Similarly, an electromagnetic signal in a radio frequency transceiver chip is guided to a PCB board in a chip packaging manner such as bonding wire (bonding wire) or flip chip (flip chip). Specifically, the apparatus shown in <FIG> specifically includes the following several parts of structures.

A carrier signal of a radio frequency sending chip is fed into a uniform substrate integrated waveguide <NUM> through a feed microstrip <NUM> with a tapered structure, to convert from a quasi-TEM mode of a carrier signal in a plane feed microstrip structure to a quasi-TE<NUM> mode of a carrier signal in the uniform substrate integrated waveguide. Further, the uniform substrate integrated waveguide <NUM> is connected to a tapered substrate integrated waveguide <NUM> for better impedance matching with a mode excitation structure <NUM>. The mode excitation structure <NUM> in <FIG> is a forward and reverse linearly tapered slot end-fire antenna.

An inner cavity of a mode conversion structure <NUM> has a rectangular cross section, an inner wall of the mode conversion structure <NUM> is metal, an eccentric position at one end of the mode conversion structure <NUM> is provided with a rectangular positioning slot <NUM>, and the other end of the mode conversion structure <NUM>, that is, a cylindrical waveguide <NUM>, may be inserted into a terahertz transmission line <NUM>. A PCB board <NUM> is inserted into the positioning slot <NUM>, so that a carrier signal sent by the end-fire antenna may be coupled into the terahertz transmission line <NUM> that is inserted into the inner cavity of the mode conversion structure <NUM>.

Similarly, some related dimensions of a feed tapered section, the metal through hole, and the positioning slot need to satisfy related conditions, to better implement carrier signal coupling. Refer to <FIG>. The related dimensions and conditions to be satisfied are the same as those in the foregoing formula <NUM> to formula <NUM>. Details are not described again.

Similarly, embodiments shown in <FIG> may be simulated. Specifically, the related dimensions include a width Wu = <NUM> between through holes of the substrate integrated waveguide at the uniform section, a width Ws = <NUM> between through holes of the substrate integrated waveguide at the feed tapered section, a length T1 = <NUM> of the substrate integrated waveguide at the feed tapered section, a metal through hole diameter d = <NUM>, a metal through hole spacing iz = <NUM>, a tapered distance iy = <NUM> of tapered metal through holes, a length L = <NUM> of the forward and reverse linearly tapered slot antenna, a bottom patch width Wl = <NUM> of the forward and reverse linearly tapered slot antenna, a quantity N = <NUM> of metal through holes at the tapered section, a quantity M = <NUM> of metal through holes that are evenly arranged on both sides of the forward and reverse linearly tapered slot antenna, a thickness St = <NUM> of a middle layer of the PCB board, a thickness Mt = <NUM> between an upper metal layer and a lower metal layer of the PCB board, a traverse width Rb = <NUM> of a rectangular metal connector, a slot height Ct = <NUM> of a metal mode converter, and a slot depth Cl = <NUM> of the metal mode converter.

According to the foregoing related dimensions, a schematic diagram of electric field mode distribution shown in <FIG> may be obtained through electromagnetic simulation calculation. An electromagnetic signal is connected from the microstrip on the PCB board to the on-chip substrate integrated waveguide, to convert from a quasi-TEM mode to a quasi-TE<NUM> mode. Then, the electromagnetic signal feeds, through the substrate integrated waveguide on the PCB board, the forward and reverse linearly tapered slot mode excitation structure whose both sides are arranged with metal through holes, to excite a transmission fundamental mode TE<NUM> mode in the rectangular metal mode conversion structure through the forward and reverse linearly tapered slot mode excitation structure on the PCB board. Then, an electromagnetic wave is coupled into the circular waveguide through the square-circular conversion mode conversion structure, to convert into a TE<NUM> mode. Then, the solid core terahertz transmission line with a tapered end face is inserted into the other end of the cylindrical waveguide, to implement fundamental mode transmission of an HE<NUM> mode. From the electric field mode distribution, it may be learned that efficient mode field conversion of the electromagnetic signal from the radio frequency transceiver chip to the terahertz transmission line may be implemented by using the mode conversion structure on the PCB board.

As shown in <FIG>, through electromagnetic simulation, it may be further learned that a transmission parameter from the microstrip on the PCB to the solid core terahertz transmission line is greater than <NUM> dB in a frequency range of <NUM> to <NUM>, and a reflection parameter is less than -<NUM> dB. This indicates that coupling efficiency is high in a very wide frequency band from the radio frequency transceiver chip to the terahertz transmission line. This helps improve a transmission distance and a communication rate of a system.

<FIG> is a side view of a terahertz carrier transceiver apparatus according to an embodiment of the present invention. A coupling apparatus with an end-fire function is designed on a package substrate <NUM> of a chip <NUM>. In this way, an electromagnetic signal does not need to pass through a package substrate layer of the chip and a solder ball pin on a PCB board <NUM>, and the electromagnetic signal is directly coupled from a chip signal to a solid core dielectric transmission line on the package substrate.

The radio frequency sending chip <NUM> feeds a carrier signal into a uniform substrate integrated waveguide <NUM> through a feed microstrip <NUM> with a tapered structure, and is further connected to a tapered substrate integrated waveguide <NUM>, to better match impedance of a mode excitation structure <NUM>. An eccentric position at one end of the mode conversion structure <NUM> is provided with a rectangular positioning slot <NUM>, and the other end of the mode conversion structure <NUM> is inserted into a terahertz transmission line <NUM>. The PCB board <NUM> and the package substrate <NUM> are inserted into the positioning slot <NUM>, so that a carrier signal sent by an end-fire antenna may be coupled to the terahertz transmission line <NUM> that is inserted into an inner cavity. Metal through holes <NUM> are arranged on both sides of the substrate integrated waveguide <NUM>/<NUM> and the end-fire antenna <NUM>. A specific design and a constraint condition are similar to those described above. Details are not described again.

<FIG> is a side view of another terahertz carrier transceiver apparatus according to an embodiment of the present invention. A coupling apparatus with an end-fire function is designed on a chip <NUM>. In this way, an electromagnetic signal does not need to pass through a package substrate layer of the chip and a solder ball pin on a PCB board. The electromagnetic signal is directly coupled from the chip to a metal mode conversion structure and then to a solid core dielectric transmission line without passing through a structure between a radio frequency transceiver chip and a package substrate.

The radio frequency sending chip <NUM> feeds a carrier signal into a uniform substrate integrated waveguide <NUM> through a feed microstrip <NUM> with a tapered structure, and is further connected to a tapered substrate integrated waveguide <NUM>, to better match impedance of a mode excitation structure <NUM>. An eccentric position at one end of the mode conversion structure <NUM> is provided with a rectangular positioning slot <NUM>, and the other end of the mode conversion structure <NUM> is inserted into a terahertz transmission line <NUM>. The PCB board <NUM>, the package substrate <NUM>, and the radio frequency transceiver chip <NUM> are inserted into the positioning slot <NUM> together, so that a carrier signal sent by an end-fire antenna may be coupled to the terahertz transmission line <NUM> that is inserted into an inner cavity of the mode conversion structure <NUM>. Metal through holes <NUM> are arranged on both sides of the substrate integrated waveguide <NUM>/<NUM> and the end-fire antenna <NUM>. A specific design and a constraint condition are similar to those described above. Details are not described again.

In embodiments shown in <FIG>, coupling efficiency is high in a very wide frequency band from the radio frequency transceiver chip to the terahertz transmission line. This helps improve a transmission distance and a communication rate of a system.

Although the present invention is described with reference to embodiments, in a process of implementing the present invention that claims protection, persons skilled in the art may understand and implement another variation of the disclosed embodiments by viewing the accompanying drawings, disclosed content, and the accompanying claims. In the claims, "comprising" (comprising) does not exclude another component or another step, and "a" or "one" does not exclude a case of multiple.

Claim 1:
A terahertz carrier sending apparatus, comprising a feed transmission line, a mode excitation structure, a mode conversion structure, a terahertz transmission line, and a circuit board, wherein
the feed transmission line is configured to: receive an electrical signal sent by a radio frequency sending circuit, and transmit the electrical signal to the mode excitation structure;
the mode excitation structure is configured to excite a terahertz signal based on the received electrical signal;
the mode conversion structure comprises an inner cavity whose inner wall is metal, and the mode excitation structure and one end of the terahertz transmission line are located in the inner cavity, so that the terahertz signal excited by the mode excitation structure is coupled into the terahertz transmission line;
the terahertz transmission line is configured to transmit the terahertz signal; and
the circuit board is configured to fasten the feed transmission line and the mode excitation structure, the mode conversion structure further comprises a positioning slot, configured to insert a part of the circuit board and the mode excitation structure into the inner cavity of the mode conversion structure, a plurality of metal through holes are distributed on both sides of the mode excitation structure, and a boundary of the positioning slot is metal and is press-fitted on the metal through holes on the both sides of the mode excitation structure.