Millimeter wave multi-channel large-bit time delay assembly

Abstract

The invention provides a multi-channel large-bit time delay assembly, which is based on a low E-plane coplanar waveguide-strip line transmission structure, reduces the area of a time delay line, and inhibits the appearance of a high-order mode at the same time. By adding an absorption shielding structure, the electromagnetic environment of the high-gain amplifier chip is improved; and the interconnection from the chip to the substrate is optimized by adopting a continuous ground plane transition mode. A high-integration multi-channel control chip is used for outputting four paths of independent delay control signals and modulation signals; a driving circuit unit is built for each channel; and finally, through reasonable layout of the four-channel six-bit delay line circuit, a component function is realized.

Description

Technical Field

[0001] The invention belongs to the field of antenna and microwave technology, and in particular relates to a millimeter wave multi-channel large-bit delay component. Background Art

[0002] The main purpose of the delay component of the radar system is to provide real-time delay for the array, compensate for the array transit time, and realize the amplification of the RF signal. Under the same stacking structure, the insertion loss of the delay line per unit length in the millimeter wave band is more than 10 times that of the X-band, and high-order modes are prone to occur; at the same time, in order to compensate for the above delay loss, the millimeter wave amplifier chip needs to achieve a higher gain (about 30dB), and when the high-gain chip is cascaded, it is easy to self-excite due to spatial coupling; and in response to the above problems, the receiving / transmitting link needs to be divided into step-by-step amplification units, resulting in a large number of chip-chip and chip-substrate interconnections. Good interconnection can ensure that the performance of the component meets the requirements. In addition, the multi-channel operation of the component involves independent control of the delay state of each channel, independent modulation of the driving circuit, reasonable layout of the delay circuit, and effective isolation of RF amplification between channels. It is not a direct splicing of single-channel delay. Therefore, the current delay components are mainly concentrated in the Ku band and below, working in the form of channel-level small position delay (below 7λ), which cannot meet the needs of array transit time compensation and millimeter wave radar systems. Summary of the invention

[0003] In order to solve the large delay and multi-channel delay components required by the millimeter wave radar system, the present invention proposes a millimeter wave multi-channel large-bit delay component, which achieves an output power of about 0.5W and a typical receiving gain of about 12dB by optimizing the delay line model, amplifier shielding cavity, and interconnection model. And with multi-channel control, modulation circuits and compact delay layout, a highly isolated working channel is realized.

[0004] The multi-channel large-bit delay component of the present invention is based on a low-E coplanar waveguide-stripline transmission structure, which reduces the area of ​​the delay line while suppressing the emergence of high-order modes; by adding an absorption shielding structure, the electromagnetic environment of the high-gain amplifier chip is improved; and a continuous ground plane transition method is used to optimize the interconnection between the chip and the substrate. A highly integrated multi-channel control chip is used to output four independent delay control signals and modulation signals; and a driving circuit unit is built for each channel; and finally, the component function is realized by rationally arranging the four-channel six-bit delay line circuit. In the four-way amplification link, the high-gain amplifier improves the isolation through a shielding cavity, an absorber and a shielding cover plate, and the four-way delay line reduces the wiring area through a multi-layer layout, thereby realizing the reliability and compactness of the component. A low-E coplanar waveguide-stripline structure is used to suppress the emergence of high-order modes, the transmission line width meets the processing accuracy requirements, the transmission line loss compensation difficulty is relatively low, and an extremely high gain amplifier is not required. Through the stepped step cavity, the transmission line and the chip are RF continuous, and the chip surface and the transmission line are at the same height, the interconnection gold wire arch height is minimized, and the RF performance is optimal.

[0005] The millimeter-wave multi-channel large-bit delay component of the present invention can achieve four channels, six bits per channel, a maximum delay of 63λ, 0.5W transmission output power and 12dB receiving gain. First, four independent delay amplification RF circuits, four independent modulation drive circuits and a multi-channel control circuit are constructed on LTCC. For the delay circuit, a chip is used to implement 1 / 2 / 4 / 8 delay bits, and a low-E-plane coplanar waveguide-stripline transmission structure is used to form 16 and 32 wavelength delay bits. The amplifier to substrate interconnection is optimized based on a continuous ground plane transition method, and the electromagnetic environment of the amplifier is improved by a shielding cavity, a shielding cover and an absorber. The modulation drive circuit consists of a high-drive capability drain generation chip and two negative reference gate voltage generation chips. The multi-channel control circuit can provide independent receive / transmit working state control and delay control for five channels. The above circuit uses low-temperature co-fired ceramic substrate materials, where L1-L7 layers are used for modulation drive and control circuit routing, L8 layer is exposed through cavities in 1-7 layers to provide reference ground for RF chips, L11, L17 and L23 respectively realize channel 16 / 32λ delay lines, L8, L14, L20, L25 and L27 are reference ground planes, and L26 is a signal routing layer for clocks, gate voltages, etc. The low-temperature co-fired ceramic substrate also includes a shielding cavity, an absorber and a shielding cover. The absorber is located below the shielding cover, and the shielding cavity is located below the absorber to improve the isolation of the delay amplification RF circuit.

[0006] The beneficial effects of the present invention are

[0007] 1. Multi-channel: The multi-channel delay of the present invention is based on a low-temperature co-fired ceramic substrate, which realizes four-channel control, amplification and a maximum delay of 63λ on each channel. The delay line layout is compact and the component integration is high.

[0008] 2. High performance: The delay line of the present invention adopts a low-E coplanar waveguide-stripline structure, which not only suppresses the emergence of high-order modes, but also achieves a balance between size, performance and processability. At the same time, based on the continuous ground plane transition method, the amplifier to substrate interconnection is optimized, and the RF performance is improved.

[0009] 3. High reliability: The four-channel four-stage amplifier of the present invention improves spatial isolation and reduces the risk of component self-excitation through a shielding cavity, a shielding cover plate and an absorber.

[0010] 4. High power: The millimeter-wave delay amplifier component of the present invention achieves a radio frequency power output of about 0.5W through performance and reliability design optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a simplified application diagram of the millimeter-wave multi-channel large-bit delay component.

[0012] Figure 2 This is the RF principle block diagram.

[0013] Figure 3 This is the control principle block diagram.

[0014] Figure 4 This is a diagram of the low-E coplanar waveguide-stripline structure.

[0015] Figure 5 Schematic diagram of the LTCC interconnect shielding model. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] refer to Figure 1 , a millimeter wave multi-channel large-bit delay component application diagram of the present invention, the receiving and transmitting links use four-stage amplifiers to achieve loss compensation and power amplification of six delay bits, and each amplifier circuit is placed in a shielded cavity, and the shielding cover and absorber are used to improve the spatial isolation and the electromagnetic environment of the high-gain amplifier. The 1 / 2 / 4 / 8λ delay chip and amplifier A are in the same shielded cavity, amplifiers B and C are in two independent cavities, and amplifiers D and E are welded on the pad. The five-channel control chip uses the first four channels to complete the delay, receive modulation and transmit modulation control of each channel of the component.

[0018] Figure 2It is a RF principle block diagram. After the transmitting signal enters from the transmitting input port, it passes through the power divider, amplifier A, 1 / 2 / 4 / 8λ delay position, amplifier B, 32λ delay position, amplifier C, 16λ delay position, amplifier D and circulator in sequence before being output; on the contrary, the receiving signal enters from the receiving input port and passes through amplifier E, 16λ delay position, amplifier C, 32λ delay position, amplifier B, 1 / 2 / 4 / 8λ delay position, amplifier A and power divider in sequence before being output.

[0019] Figure 3 This is the control principle block diagram. After the control signal and power signal enter the five-channel control chip, the first four channels output independent signals to the gate voltage A generating chip, the gate voltage B generating chip and the transceiver modulation chip respectively, and then power is supplied to each level of amplifier. The fifth channel of the control chip is not used.

[0020] Figure 4 It is a low E-plane coplanar waveguide-stripline model. This model suppresses the transmission of high-order modes by reducing the E-plane height. At the same time, the stripline structure is combined to concentrate the electromagnetic field near the transmission line. In the circuit constructed using low-temperature co-fired ceramics (LTCC), the E-plane height is 0.6mm and the transmission line width is 0.2mm.

[0021] Figure 5 This is an LTCC interconnection shielding model. First, LTCC provides good spatial isolation for the amplifier through the stepped cavity of W1-6 and W1-7. Secondly, the absorber and shielding cover are combined to improve the electromagnetic environment above the high-gain amplifier to avoid electromagnetic leakage. In addition, the construction of the stepped cavity makes the chip reference ground and the L7 layer RF routing signal ground continuous. At the same time, the chip surface and the L7 layer are flush to reduce the bonding wire arch height and optimize the interconnection performance. The L11 layer is the 32λ delay routing of channels one and three, the L17 layer is the 32λ delay routing of channels two and four, the L23 layer is the 16λ delay routing of four channels, and the remaining wiring layers are control signals.

[0022] The present invention is not limited to the above specific implementations, and the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the above implementations based on the technical essence of the present invention shall be included in the protection scope of the present invention.

Claims

1. A millimeter wave multi-channel large bit delay component, characterized in that: It includes four independent time-delay amplification radio frequency circuits, four independent modulation drive circuits and a multi-channel control circuit; The delay amplification RF circuit can achieve 1 / 2 / 4 / 8 / 16 / 32 delay bits; The modulation drive circuit is composed of a drain voltage generation chip and two negative reference gate voltage generation chips; The multi-channel control circuit can provide independent receiving / transmitting working state control and delay control for five channels; The delay amplification RF circuit, modulation drive circuit and multi-channel control circuit use low-temperature co-fired ceramic substrates, among which L1-L7 layers are used for modulation drive circuit and multi-channel control circuit routing. The L8 layer is exposed by digging a cavity to provide a reference ground for the RF chip. L11, L17 and L23 respectively realize channel 16 / 32λ delay lines. L8, L14, L20, L25 and L27 are reference ground planes, and L26 is a signal routing layer for clocks, gate voltages, etc.

2. A millimeter wave multi-channel large bit delay component according to claim 1, characterized in that: The delay amplification RF circuit uses chips to implement 1 / 2 / 4 / 8 delay bits and uses a low-E coplanar waveguide-stripline transmission structure to form 16 and 32 wavelength delay bits.

3. A millimeter wave multi-channel large bit delay component according to claim 2, characterized in that: The low-temperature co-fired ceramic substrate also includes a shielding cavity, an absorber and a shielding cover plate. The absorber is located below the shielding cover plate, and the shielding cavity is located below the absorber, so as to improve the isolation of the delay amplification radio frequency circuit.

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