A high-power, high-isolation transmitting device

Abstract

This invention relates to the field of radio frequency communication technology and discloses a high-power, high-isolation transmitting device, comprising a microwave local oscillator circuit, a local oscillator power divider circuit, an isolation circuit, a phase modulation circuit, a microwave switching circuit, a power amplifier circuit, and a power supply circuit connected in sequence. The microwave switching circuit uses multi-stage cascaded switching chips with an inter-stage spacing of λ / 2, and the microstrip transmission line is isolated by a metal wall. The power amplifier circuit uses a two-stage drive amplification followed by power division into four final stages for amplification. The radio frequency circuit is arranged in a cavity-layered layout, and the outer cover of the cavity is sealed by laser welding. This invention can achieve high power and high isolation simultaneously. The power amplifier structure with a two-stage drive amplification followed by power division into four final stages enables a single-channel output power greater than 40dBm. The isolation of the microwave switching module is greater than 100dB, and the overall switching isolation reaches more than 90dB, breaking through the technical limitations of traditional devices that cannot simultaneously achieve high power and isolation.

Description

Technical Field

[0001] This invention relates to the field of radio frequency communication technology. Background Technology

[0002] The radio frequency (RF) transmitter is a core component of the RF TR module and transceiver system. Its function is to modulate and amplify the local oscillator signal before radiating it through the antenna, thus enabling the receiver to extract target information. The transmitted signal operates in a time-division multiplexing mode, and the isolation degree of the transmit switch directly determines the system's receiving sensitivity, making it a key technical indicator.

[0003] Existing traditional transmitting devices generally adopt a structure where the radio frequency (RF) microwave circuits and power supply circuits are arranged in separate cavities, with the cavity covers secured by screws. The RF and power supply circuits are distributed on the front and back of the cavity, and power supply and signal control are achieved through feedthrough capacitors. This design has significant drawbacks: 1. The cavity is only fastened with screws, resulting in poor sealing. Radio frequency signals are easily leaked to the power amplifier through spatial coupling, leading to insufficient turn-off isolation. The isolation index of the switch itself must be sacrificed to barely meet the system requirements. 2. Due to limitations in semiconductor physical characteristics, processing technology, heat dissipation, and impedance matching, traditional transmitters typically only achieve an output power of 30dBm and a switching isolation of less than 80dB, making it impossible to simultaneously improve high power output and high switching isolation. 3. Crosstalk in the signal link, power supply interference, and space radiation leakage are difficult to suppress, resulting in large device size, complex debugging, and low production efficiency, which cannot meet the usage requirements of high-sensitivity transceiver systems.

[0004] As military and civilian communication and detection systems develop towards higher power, higher integration, and higher sensitivity, traditional transmitting devices can no longer simultaneously meet the dual requirements of high power output and high transmit / receive isolation, becoming a key bottleneck restricting the improvement of system performance. Summary of the Invention

[0005] The purpose of this invention is to provide a high-power, high-isolation transmitting device. Through the overall design of multi-stage switch chip cascading, λ / 2 stage isolation, metal wall isolation, two-stage drive power divider amplification, cavity-divided layered layout, and laser-sealed outer cover plate, it effectively blocks radio frequency signal coupling and spatial leakage under high-power output conditions, and simultaneously achieves high output power and high switching isolation.

[0006] To address the aforementioned technical problems, this invention provides a high-power, high-isolation transmitting device, comprising a microwave local oscillator circuit, a local oscillator power divider circuit, an isolation circuit, a phase modulation circuit, a microwave switching circuit, a power amplifier circuit, and a power supply circuit for power supply, connected in sequence. The microwave switching circuit employs multi-stage cascaded switching chips with an inter-stage spacing of λ / 2, and the microstrip transmission line is isolated by a metal wall. The power amplifier circuit employs a two-stage drive amplification followed by power division into four final stages for amplification. The radio frequency circuit is arranged in a cavity-layered layout, and the outer cover plate of the cavity is sealed by laser welding.

[0007] The microwave switching circuit uses a cascaded three-stage single-pole single-throw switch chip, and the isolation of the switching module is greater than 100dB.

[0008] The power amplifier circuit includes a driver stage power amplifier and a final stage power amplifier, with a single-channel output power greater than 40dBm and a transmitter switching isolation greater than 90dB.

[0009] The local oscillator power divider circuit includes an unequal power divider and an adjustable attenuator, which divides the local oscillator signal into a receiving mixing branch and a transmitting modulation amplification branch.

[0010] The isolation circuit connects the local oscillator power divider circuit and the phase modulation circuit to suppress crosstalk between the local oscillator signal and the phase modulation signal.

[0011] The phase modulation circuit is a binary phase shift keying modulator, which realizes phase switching between 0° and 180° of the carrier signal.

[0012] The front-end small-signal radio frequency circuit and the back-end power amplifier circuit of the microwave switching circuit are set in separate cavities and are connected by a radio frequency cable.

[0013] The radio frequency circuit cavity is provided with an inner cover plate and an outer cover plate. The inner cover plate is assembled with screws, and the outer cover plate is laser-sealed to the cavity for sealing.

[0014] The power supply circuit includes multiple DC / DC conversion circuits and switching control circuits to achieve independent power supply and time-division control of the microwave local oscillator and power amplifier circuits.

[0015] The transmitting device has a four-channel structure, enabling time-sharing output from each of the four channels.

[0016] Compared with the prior art, this invention can achieve high power and high isolation simultaneously. It adopts a power amplifier structure with two-stage drive amplification followed by power division into four final stages, so that the single-channel output power is greater than 40dBm; the microwave switch module isolation is greater than 100dB, and the overall switch isolation reaches more than 90dB, breaking through the technical limitations of traditional devices that cannot balance power and isolation. To completely block RF signal leakage, the microwave switch uses a three-stage single-pole single-throw switch chip cascaded with a λ / 2 stage spacing and metal wall isolation to suppress interstage coupling and link leakage; the RF circuit adopts a cavity-separated layered layout for small signal circuits and power amplifier circuits, combined with a double-layer sealing structure of inner layer screw assembly and outer layer laser sealing, to completely eliminate cavity gap leakage and spatial radiation, and significantly improve turn-off isolation performance. The circuit structure is simplified and meets the requirements without debugging. The power amplifier circuit adopts a symmetrical power divider topology, which reduces the number of high-frequency circuit layers and simplifies the design of low-frequency circuits. The device adopts a modular integrated design, which can meet the requirements of high power and high isolation as soon as it is assembled. No on-site debugging is required, which reduces R&D and manufacturing costs and improves mass production efficiency. Multi-path signal crosstalk suppression: the isolation circuit blocks crosstalk between the local oscillator branch and the modulation branch; the power supply adopts multi-channel independent DC / DC conversion and separate power supply to eliminate low-frequency power supply crosstalk; four-channel time-division output in pairs avoids mutual interference between channels and improves the overall working stability. The device is miniaturized and highly integrated, adopting a modular and compact layout and a compartmentalized and layered structure. It achieves four channels, high power, and high isolation while reducing the overall size of the device, making it suitable for highly integrated transceiver systems such as airborne and shipborne systems. The system's receiving sensitivity is improved, and the extremely low leakage signal in the off state avoids mis-amplification by the subsequent power amplifier, reducing system noise at the source, significantly improving the receiving sensitivity of the transceiver system, and enhancing the reliability of system detection and communication.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a schematic diagram of the connection principle of at least one embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the installation structure of a microwave switch; Figure 3 yes Figure 1 A schematic diagram of the installation structure of the radio frequency circuit.

[0020] In the diagram: 11-Microwave switch, 12-RF cable, 13-Inner layer, 14-Outer layer. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0022] Example 1 like Figure 1 The transmitter shown includes a microwave local oscillator circuit, a local oscillator power divider circuit, an isolation circuit, a phase modulation circuit, a microwave switching circuit, a power amplifier circuit, and a power supply circuit connected in sequence. The microwave switching circuit uses multi-stage cascaded switching chips with an inter-stage spacing of λ / 2, and the microstrip transmission line is isolated by a metal wall. The power amplifier circuit uses a two-stage drive amplification followed by power division into four final stages for amplification. The radio frequency circuit is arranged in a cavity-layered layout, and the outer cover of the cavity is sealed by laser welding.

[0023] The microwave local oscillator circuit employs phase-locked loop (PLL) frequency synthesis technology to generate a stable local oscillator signal, providing a carrier signal for the local oscillator port of the transmitting device and subsequent modulation and amplification circuits. The local oscillator power divider circuit splits the local oscillator signal into two paths: one for the receiving device's mixing and the other for the subsequent modulation and amplification link. An isolation circuit connects the local oscillator power divider circuit and the phase modulation circuit, blocking crosstalk between the phase modulation circuit and the local oscillator signal in the receiving branch. The phase modulation circuit performs phase modulation on the carrier signal to achieve information loading. The microwave switching circuit, under the action of an external control signal, completes the rapid on / off of the RF signal. Cascading multiple switching chips with a λ / 2 stage spacing suppresses inter-stage signal coupling and leakage, and the outer metal wall of the microstrip transmission line further reduces spatial radiation. The power amplifier circuit, after amplification by two stages of drive stages, is divided into four paths by a power divider for final stage power amplification, increasing the output power of a single channel. The power supply circuit provides a stable operating voltage for each functional module and implements time-division multiplexing control of the modules. The RF circuit is divided into cavities and layers to physically separate small signal circuits from high power circuits. The outer cover is laser-sealed to eliminate leakage from cavity gaps and block the spatial radiation path of RF signals.

[0024] This embodiment simultaneously suppresses RF signal coupling and leakage from both the circuit link and structural sealing aspects, enabling the transmitter to maintain high shutdown isolation under high power output conditions. This solves the problem that the output power and switching isolation of traditional transmitters cannot be improved synchronously. Once assembled, it can meet the performance requirements without additional debugging, reducing production costs and improving production efficiency.

[0025] Example 2 Based on Example 1, the microwave switching circuit uses a cascaded three-stage single-pole single-throw switch chip, and the isolation of the switching module is greater than 100dB.

[0026] Furthermore, the local oscillator power divider circuit includes an unequal power divider and an adjustable attenuator, which divides the local oscillator signal into a receiving mixing branch and a transmitting modulation amplification branch.

[0027] Furthermore, the isolation circuit connects the local oscillator power divider circuit and the phase modulation circuit to suppress crosstalk between the local oscillator signal and the phase modulation signal.

[0028] Furthermore, the phase modulation circuit is a binary phase shift keying modulator, which realizes the phase switching of the carrier signal from 0° to 180°.

[0029] Furthermore, the small-signal radio frequency circuit at the front end of the microwave switching circuit and the power amplifier circuit at the back end are set in separate cavities, and the two are connected by a radio frequency cable.

[0030] Furthermore, the radio frequency circuit cavity is equipped with an inner cover plate and an outer cover plate. The inner cover plate is assembled with screws, and the outer cover plate is laser-sealed to the cavity for sealing.

[0031] Furthermore, the power supply circuit includes multiple DC / DC conversion circuits and switching control circuits to achieve independent power supply and time-division control for the microwave local oscillator and power amplifier circuits.

[0032] Three-stage single-pole single-throw (SPST) switch chips are cascaded sequentially along the signal transmission direction, with a transmission line length of λ / 2 between adjacent chips, forming a phase cancellation structure to reduce inter-stage interference and signal leakage. The microstrip transmission line employs full metal-wall isolation, reducing the microstrip package height and the distance between the line and the cavity sidewall, compressing the radiation space. Combined with attenuators, temperature-compensated attenuators, and amplifiers, the isolation of the switch module is greater than 100dB. The local oscillator power divider circuit uses an unequal power divider and an adjustable attenuator to achieve signal distribution and amplitude adjustment, meeting the requirements of both receiving and transmitting signals. The isolation circuit uses impedance matching and physical isolation to prevent crosstalk between the two signals. The binary phase-shift keying modulator drives the carrier wave with a continuous square wave, achieving 0° and 180° phase transitions to complete digital modulation. The front-end small-signal RF circuit and the back-end power amplifier circuit of the microwave switch 11 are arranged in separate cavities, connected by an RF cable 12 for physical isolation, preventing interference from high-power signals to the small-signal circuit. The RF cavity employs a double-layer cover structure with 13 screws for inner assembly and 14 laser-sealed outer layers. The inner layer ensures assembly precision, while the outer layer provides a complete seal, eliminating any leakage of RF signals. The power supply circuit converts the external +28V input to +7V, -5V, and other suitable voltages via multiple DC / DC converters, supplying the local oscillator, phase modulation circuit, microwave switch, and power amplifiers at each stage. The switch control circuit independently powers on and off each module based on external commands, reducing low-frequency crosstalk.

[0033] This embodiment comprehensively blocks signal crosstalk and leakage paths through the collaborative design of cascaded optimization of switch chips, signal link isolation, cavity layout, double-layer sealing and independent power supply, significantly improving the turn-off isolation, while ensuring the stability of signal modulation and power output. This enables the transmitter to maintain excellent performance under complex working conditions, breaking through the limitations of isolation that relies on a single switch device in traditional designs, and achieving stronger anti-leakage and anti-interference capabilities.

[0034] Example 3 Based on Embodiment 1, the power amplifier circuit includes a driver stage power amplifier and a final stage power amplifier, with a single-channel output power greater than 40dBm and a transmitter switching isolation greater than 90dB.

[0035] Furthermore, the transmitter has a four-channel structure, enabling time-sharing output from each of the four channels.

[0036] The power amplifier circuit sends the microwave switch output signal to a power divider, splitting it into two symmetrical links. Each link first undergoes drive amplification by a driver-stage power amplifier, then is isolated between stages before being split into two paths by the power divider and sent to the final stage power amplifier for full-power output, ultimately forming four independent output channels. The two-stage amplifier circuit adopts a symmetrical layout, optimizing impedance matching and reducing signal reflection and loss, resulting in a single-channel output power greater than 40dBm. The four channels operate in a two-way time-division multiplexing mode, with adjacent channels being turned on and off in a time-division manner to avoid mutual interference between channels. Combined with the high isolation performance of the microwave switch and the fully sealed cavity structure, the overall switching isolation of the transmitter is greater than 90dB.

[0037] This embodiment uses a simple topology with two-stage drive and four-channel final stage amplification to achieve high power output with fewer cascaded stages, reducing circuit complexity, heat dissipation pressure, and debugging difficulty, and overcoming the problems of power limitation and impedance matching difficulty of solid-state devices. At the same time, through four-channel pairwise time-division control and high isolation design, the overall isolation is improved to more than 90dB under the premise of high power output, realizing the synchronous improvement of output power and switching isolation, meeting the comprehensive requirements of high sensitivity, high power, and high isolation of transceiver systems, and has significant technical advantages compared with traditional transmitting devices.

[0038] Therefore, to meet the requirements of multi-channel and high-power output of the transmitting device, this invention selects a relatively small number of cascaded post-amplifier circuits to achieve higher power output. The post-amplifier circuit adopts a symmetrical arrangement of power dividers, and the power is divided into four paths for final power amplification after two stages of driver amplification, reducing the high-frequency circuit structure and simplifying the low-frequency circuit design. To meet the high isolation requirements of the transmitting device, on the one hand, the microwave switch adopts a modular design, and the internal switching chips are cascaded to achieve a signal isolation of more than 100dB between switch on and off. On the other hand, in terms of structure, the small-signal microwave circuit before the microwave switch and the post-amplifier circuit are arranged in separate cavities and layers, and the corresponding power supply circuits are independently powered to reduce crosstalk of low-frequency circuit signals. The cover plate of the microwave circuit is made of inner and outer cover plates, and the outer cover plate is welded to the cavity by laser sealing to reduce radio frequency leakage and achieve the high isolation requirements of the transmitting device.

[0039] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. A high-power, high-isolation transmitting device, characterized in that, It includes a microwave local oscillator circuit, a local oscillator power divider circuit, an isolation circuit, a phase modulation circuit, a microwave switch circuit, a power amplifier circuit, and a power supply circuit for power supply, all connected in sequence. The microwave switch circuit uses multi-stage cascaded switch chips with an inter-stage spacing of λ / 2, and the microstrip transmission line is isolated by a metal wall. The power amplifier circuit uses a two-stage drive amplification followed by power division into four final stages for amplification. The radio frequency circuit is arranged in a cavity-layered layout, and the outer cover of the cavity is sealed by laser welding.

2. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The microwave switching circuit uses a cascaded three-stage single-pole single-throw switch chip, and the isolation of the switching module is greater than 100dB.

3. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The power amplifier circuit includes a driver stage power amplifier and a final stage power amplifier, with a single-channel output power greater than 40dBm and a transmitter switching isolation greater than 90dB.

4. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The local oscillator power divider circuit includes an unequal power divider and an adjustable attenuator, which divides the local oscillator signal into a receiving mixing branch and a transmitting modulation amplification branch.

5. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The isolation circuit connects the local oscillator power divider circuit and the phase modulation circuit to suppress crosstalk between the local oscillator signal and the phase modulation signal.

6. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The phase modulation circuit is a binary phase shift keying modulator, which realizes phase switching between 0° and 180° of the carrier signal.

7. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The front-end small-signal radio frequency circuit and the back-end power amplifier circuit of the microwave switching circuit are set in separate cavities and are connected by a radio frequency cable.

8. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The radio frequency circuit cavity is provided with an inner cover plate and an outer cover plate. The inner cover plate is assembled with screws, and the outer cover plate is laser-sealed to the cavity for sealing.

9. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The power supply circuit includes multiple DC / DC conversion circuits and switching control circuits to achieve independent power supply and time-division control of the microwave local oscillator and power amplifier circuits.

10. The high-power, high-isolation transmitting device according to claim 1, characterized in that, The transmitting device has a four-channel structure, enabling time-sharing output from each of the four channels.

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