A GNSS antenna LNA amplifier circuit

Abstract

The present invention provides a GNSS antenna LNA amplifier circuit, comprising a first-stage amplifier circuit for satellite signals of a first frequency band, a first-stage amplifier circuit for satellite signals of a second frequency band, and a second-stage amplifier circuit, wherein the GNSS antenna is connected to the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band, and the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band are connected to the second-stage amplifier circuit. The present invention uses an amplifier circuit of a low-noise amplifier chip and a double-stage filter, which can effectively filter and suppress interference signals outside the frequency band, improve the overall anti-interference ability of the antenna, ensure that the amplified signal has a higher signal-to-noise ratio, and ensure the normal operation of the GNSS antenna and the navigation system can still receive satellite signals in complex environments.

Description

Technical Field

[0001] The present invention relates to the technical field of global navigation satellite system positioning, and in particular to a GNSS antenna LNA amplifier circuit. Background Art

[0002] With the gradual maturity of global satellite navigation and positioning technology, satellite navigation technology has basically replaced ground-based radio navigation, traditional geodetic and astronomical measurement navigation and positioning technology, and promoted the new development of geodetic and navigation and positioning fields. The GNSS system is not only the infrastructure of national security and economy, but also an important symbol of the status of a modern great power and the comprehensive national strength of a country. As satellite navigation and positioning technology has important significance in politics, economy, and military, the world's major military powers and economies are competing to develop independent satellite navigation systems, such as the US GPS, Russia's GLONASS, the EU's GALILEO and China's Beidou satellite navigation system, which will be built or completed. The GNSS antenna is a necessary equipment for the satellite navigation and positioning system. Whether the satellite navigation and positioning signal can be received depends on the signal processing of the antenna device and the front-end amplifier circuit. The existing GNSS antenna amplifier circuit cannot effectively filter and suppress interference signals outside the frequency band, and the signal-to-noise of the amplified signal is low, resulting in the navigation system being unable to receive satellite signals in complex environments. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a GNSS antenna LNA amplifier circuit, which uses a low-noise amplifier chip and a double-stage filter amplifier circuit to effectively filter and suppress interference signals outside the frequency band, ensure that the amplified signal has a higher signal-to-noise ratio, and ensure that the navigation system can still receive satellite signals in complex environments.

[0004] The present invention provides a GNSS antenna LNA amplifier circuit, comprising a first-stage amplifier circuit for a satellite signal of a first frequency band, a first-stage amplifier circuit for a satellite signal of a second frequency band, and a second-stage amplifier circuit. The GNSS antenna is connected to the first-stage amplifier circuit for the satellite signal of the first frequency band and the first-stage amplifier circuit for the satellite signal of the second frequency band, and the first-stage amplifier circuit for the satellite signal of the first frequency band and the first-stage amplifier circuit for the satellite signal of the second frequency band are connected to the second-stage amplifier circuit.

[0005] Furthermore, the first-stage amplification circuit for satellite signals in the first frequency band and the first-stage amplification circuit for satellite signals in the second frequency band both include a first-stage filter, a first-stage amplification chip, a second-stage filter, an interstage matching resistor, an interstage matching capacitor, and an interstage matching inductor. The GNSS antenna is connected to the input end of the first-stage filter, the output end of the first-stage filter is connected to the interstage matching resistor, the interstage matching resistor is connected in series with the interstage matching capacitor, the interstage matching capacitor is connected to the input end of the first-stage amplification chip, one end of the interstage matching inductor is connected between the interstage matching resistor and the interstage matching capacitor, the other end of the interstage matching inductor is grounded, the output end of the first-stage amplification chip is connected to the input end of the second-stage filter, and the output end of the second-stage filter is connected to the second-stage amplification circuit.

[0006] Furthermore, the first-frequency-band satellite signal first-stage amplifier circuit and the second-frequency-band satellite signal first-stage amplifier circuit both include a first resistor, and the GNSS antenna is connected to the input end of the first-stage filter via the first resistor.

[0007] Furthermore, the first-stage amplifying circuit for satellite signals of the first frequency band and the first-stage amplifying circuit for satellite signals of the second frequency band both include a first inductor and a first capacitor. The output end of the first-stage amplifying chip is connected to a power supply through the first inductor, and the output end of the first-stage amplifying chip is connected to an input end of the second-stage filter through the first capacitor.

[0008] Furthermore, the second-stage amplifier circuit includes a second-stage amplifier chip and a third-stage amplifier chip, and the second-stage filters of the first-stage amplifier circuit for the first-frequency band satellite signal and the first-stage amplifier circuit for the second-frequency band satellite signal are both connected to the input end of the second-stage amplifier chip, and the output end of the second-stage amplifier chip is connected to the input end of the third-stage amplifier chip.

[0009] Furthermore, the second-stage amplifier circuit also includes a second inductor and a second capacitor. The second-stage filters of the first-stage amplifier circuit for satellite signals in the first frequency band and the first-stage amplifier circuit for satellite signals in the second frequency band are both connected to the second inductor. The second inductor is connected in series with the second capacitor. The second capacitor is connected to the input end of the second-stage amplifier chip.

[0010] Further, the second-stage amplifier circuit also includes a first gain resistor, a second gain resistor, a third inductor, a third capacitor, a fourth inductor, a fourth capacitor, and an output matching circuit, wherein the output matching circuit includes a fifth capacitor, a second resistor, a third resistor, a fourth resistor, and a sixth capacitor, the output end of the second-stage amplifier chip is connected to the first gain resistor, the first gain resistor is connected to the third inductor, one end of the second gain resistor is connected between the first gain resistor and the third inductor, and the other end is grounded, the third inductor is connected in series with the third capacitor, the third capacitor is connected to the input end of the third-stage amplifier chip, one end of the fourth inductor is connected in series with one end of the fourth capacitor, the other end of the fourth inductor is connected between the third capacitor and the input end of the third-stage amplifier chip, the other end of the fourth capacitor is grounded, the fifth capacitor, the second resistor, and the sixth capacitor are connected in series in sequence, the fifth capacitor is connected to the output end of the third-stage amplifier chip, one end of the third resistor is connected between the fifth capacitor and the second resistor, and the other end is grounded, one end of the fourth resistor is connected between the second resistor and the sixth capacitor, and the other end is grounded.

[0011] Furthermore, the first-stage amplifying circuit for satellite signals of the first frequency band, the first-stage amplifying circuit for satellite signals of the second frequency band, and the second-stage amplifying circuit all include a decoupling circuit, and the decoupling circuit is connected to a power supply.

[0012] Furthermore, the decoupling circuit includes a first decoupling capacitor and a second decoupling capacitor, the first decoupling capacitor and the second decoupling capacitor are connected in parallel, one end of the parallel circuit of the first decoupling capacitor and the second decoupling capacitor is grounded, and the other end is connected to a power supply.

[0013] Furthermore, the first-stage amplifier circuit for the satellite signal in the first frequency band is a first-stage amplifier circuit for the satellite signal in the 1.2G frequency band, the first-stage amplifier circuit for the satellite signal in the second frequency band is a first-stage amplifier circuit for the satellite signal in the 1.5G frequency band, the first-stage amplifier chip is an amplifier chip with a gain of 18dB and a noise of 0.3dB, the second-stage amplifier chip and the third-stage amplifier chip are amplifier chips with a gain of 14dB and a noise of 1dB, and the first-stage filter and the second-stage filter are dielectric filters.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention provides a GNSS antenna LNA amplifier circuit, comprising a first-stage amplifier circuit for satellite signals of a first frequency band, a first-stage amplifier circuit for satellite signals of a second frequency band, and a second-stage amplifier circuit, wherein the GNSS antenna is connected to the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band, and the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band are connected to the second-stage amplifier circuit. The present invention uses an amplifier circuit of a low-noise amplifier chip and a double-stage filter, which can effectively filter and suppress interference signals outside the frequency band, thereby improving the overall anti-interference ability of the antenna, and by using an amplifier chip with a first-stage noise of 0.3dB for amplification processing, the overall noise coefficient of the circuit is effectively reduced, and then the second-stage and third-stage amplifier chips are used for amplification processing, ensuring sufficient amplification gain, thereby ensuring that the amplified signal has a higher signal-to-noise ratio, and ensuring the normal operation of the GNSS antenna and the navigation system can still receive satellite signals in a complex environment.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic diagram of a GNSS antenna LNA amplifier circuit of the present invention;

[0019] Figure 2 This is the first stage amplification circuit diagram of the 1.2G frequency band satellite signal of the present invention;

[0020] Figure 3 This is the first stage amplification circuit diagram of the 1.5G frequency band satellite signal of the present invention;

[0021] Figure 4 This is the second stage amplification circuit diagram of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0023] A GNSS antenna LNA amplifier circuit, such as Figure 1As shown, it includes a first-stage amplifier circuit for satellite signals of a first frequency band, a first-stage amplifier circuit for satellite signals of a second frequency band, and a second-stage amplifier circuit. The GNSS antenna is connected to the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band. The first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band are connected to the second-stage amplifier circuit.

[0024] like Figure 1-Figure 3 As shown, the first-stage amplifying circuit for satellite signals of the first frequency band and the first-stage amplifying circuit for satellite signals of the second frequency band both include a first-stage filter, a first-stage amplifying chip, a second-stage filter, an inter-stage matching resistor, an inter-stage matching capacitor, an inter-stage matching inductor, a first resistor, a first inductor, a first capacitor, and a decoupling circuit, and the decoupling circuit includes a first decoupling capacitor and a second decoupling capacitor. Figure 1-Figure 3 In the figure, the first filter of the first amplifier circuit of the satellite signal of the first frequency band is represented by Filter1, the first amplifier chip is represented by AMP1 or U1, the second filter is represented by Filter2, the interstage matching resistor is represented by R2, the interstage matching capacitor is represented by C1, the interstage matching inductor is represented by L1, the first resistor is represented by R1, the first inductor is represented by L3, the first capacitor is represented by C4, the first decoupling capacitor is represented by C2, and the second decoupling capacitor is represented by C3. The first filter of the first amplifier circuit of the satellite signal of the second frequency band is represented by Filter3, the first amplifier chip is represented by AMP1 or U2, the second filter is represented by Filter4, the interstage matching resistor is represented by R4, the interstage matching capacitor is represented by C5, the interstage matching inductor is represented by L2, the first resistor is represented by R3, the first inductor is represented by L4, the first capacitor is represented by C8, the first decoupling capacitor is represented by C6, and the second decoupling capacitor is represented by C7.

[0025] like Figure 2 As shown, the GNSS antenna is connected to the input of Filter1 through R1, the output of Filter1 is connected to R2, R2 is connected in series with C1, C1 is connected to the input of U1, one end of L1 is connected between R2 and C1, the other end of L1 is grounded, the output of U1 is connected to the 3V power supply through L3, the output of U1 is connected to the input of Filter2 through C4, the output of Filter2 is connected to the second-stage amplifier circuit, C2 and C3 are connected in parallel, one end of the parallel circuit of C2 and C3 is grounded, and the other end is connected to the 3V power supply. The 1.2G frequency band signal enters the first-stage filter Filter1 through the resistor R1, enters the first-stage amplifier chip U1 through the inter-stage matching of the resistor R2, the capacitor C1, and the inductor L1, and enters the second-stage filter Filter2 after the signal is amplified through the matching of the inductor L3 and the capacitor C4. The capacitor C2 and the capacitor C3 perform decoupling processing on the power supply signal.

[0026] like Figure 3As shown, the GNSS antenna is connected to the input of Filter3 through R3, the output of Filter3 is connected to R4, R4 is connected in series with C5, C5 is connected to the input of U2, one end of L2 is connected between R4 and C5, the other end of L2 is grounded, the output of U2 is connected to the 3V power supply through L4, the output of U2 is connected to the input of Filter4 through C8, the output of Filter4 is connected to the second-stage amplifier circuit, C6 is connected in parallel with C7, one end of the parallel circuit of C6 and C7 is grounded, and the other end is connected to the 3V power supply. The 1.5G frequency band signal enters the first-stage filter Filter3 through the resistor R3, enters the first-stage amplifier chip U2 through the inter-stage matching of the resistor R4, the capacitor C5, and the inductor L2, and after the signal is amplified, it enters the second-stage filter Filter4 through the matching of the inductor L4 and the capacitor C8, and the capacitor C6 and the capacitor C7 perform decoupling processing on the power supply signal.

[0027] like Figure 1 , Figure 4 As shown, the second-stage amplifier circuit includes a second-stage amplifier chip, a third-stage amplifier chip, a second inductor, a second capacitor, a first gain resistor, a second gain resistor, a third inductor, a third capacitor, a fourth inductor, a fourth capacitor, an output matching circuit, and a decoupling circuit. The output matching circuit includes a fifth capacitor, a second resistor, a third resistor, a fourth resistor, and a sixth capacitor. The decoupling circuit includes a first decoupling capacitor and a second decoupling capacitor. Figure 1 , Figure 4 In the figure, the second-stage amplifier chip is represented by AMP2 or Q1, the third-stage amplifier chip is represented by AMP2 or Q2, the second inductor is represented by L5, the second capacitor is represented by C14, the first gain resistor is represented by R5, the second gain resistor is represented by R6, the third inductor is represented by L6, the third capacitor is represented by C17, the fourth inductor is represented by L7, the fourth capacitor is represented by C15, the fifth capacitor is represented by C13, the second resistor is represented by R8, the third resistor is represented by R7, the fourth resistor is represented by R9, the sixth capacitor is represented by C16, the first decoupling capacitors are represented by C11 and C9, and the second decoupling capacitors are represented by C12 and C10.

[0028] The output ends of Filter2 and Filter4 are both connected to L5, L5 is connected in series with C14, C14 is connected to the input end of Q1, the output end of Q1 is connected to R5, R5 is connected to L6, one end of R6 is connected between R5 and L6, and the other end is grounded, L6 is connected in series with C17, C17 is connected to the input end of Q2, one end of L7 is connected in series with one end of C15, the other end of L7 is connected between C17 and the input end of Q2, and the other end of C15 is grounded, C13, R8, and C16 are connected in series in sequence, C13 is connected to the output end of Q2, one end of R7 is connected between C13 and R8, and the other end is grounded, one end of R9 is connected between R8 and C16, and the other end is grounded, C9 and C10 are connected in parallel, one end of the parallel circuit of C9 and C10 is grounded, and the other end is connected to a 3V power supply, C11 and C12 are connected in parallel, one end of the parallel circuit of C11 and C12 is grounded, and the other end is connected to a 3V power supply.

[0029] After the 1.2G band and 1.5G band signals are combined, they enter the second-stage amplifier chip Q1 after being matched by inductor L5 and capacitor C14. Resistors R5 and R6 can appropriately adjust the gain of the circuit. After being matched by inductor L6, capacitor C17, inductor L7, and capacitor C15, they enter the third-stage amplifier chip Q2. Finally, output matching is performed through capacitor C13, resistor R7, resistor R8, resistor R9, and capacitor C16. Capacitors C9, C10, C11, and C12 decouple the power supply signal.

[0030] In one embodiment, the first-stage amplifier circuit for the satellite signal of the first frequency band is the first-stage amplifier circuit for the satellite signal of the 1.2G frequency band, and the first-stage amplifier circuit for the satellite signal of the second frequency band is the first-stage amplifier circuit for the satellite signal of the 1.5G frequency band. The GNSS antenna receives satellite signals of the 1.2G frequency band and the 1.5G frequency band, and the 1.2G frequency band signal and the 1.5G frequency band signal are respectively filtered out of the frequency band by the first-stage filter and enter the first-stage low-noise amplifier chip for signal amplification processing, and then pass through the second-stage filter to suppress the signal outside the channel, and then the 1.2G frequency band signal and the 1.5G frequency band signal are combined and amplified by the second-stage amplifier chip and the third-stage amplifier chip. In this embodiment, the first-stage amplifier chip is an amplifier chip with a gain of 18dB and a noise of 0.3dB, and the second-stage amplifier chip and the third-stage amplifier chip are amplifier chips with a gain of 14dB and a noise of 1dB. By using the first-stage amplifier chip with a noise of 0.3dB for amplification processing, the overall noise coefficient of the circuit is effectively reduced, and then the second-stage and third-stage amplifier chips are used for amplification processing to ensure sufficient amplification gain, thereby ensuring that the amplified signal has a higher signal-to-noise ratio. The first-stage filter and the second-stage filter are dielectric filters, which filter and suppress signals outside the required frequency band.

[0031] The present invention provides a GNSS antenna LNA amplifier circuit, comprising a first-stage amplifier circuit for satellite signals of a first frequency band, a first-stage amplifier circuit for satellite signals of a second frequency band, and a second-stage amplifier circuit, wherein the GNSS antenna is connected to the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band, and the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band are connected to the second-stage amplifier circuit. The present invention uses an amplifier circuit of a low-noise amplifier chip and a double-stage filter, which can effectively filter and suppress interference signals outside the frequency band, thereby improving the overall anti-interference ability of the antenna, and by using an amplifier chip with a first-stage noise of 0.3dB for amplification processing, the overall noise coefficient of the circuit is effectively reduced, and then the second-stage and third-stage amplifier chips are used for amplification processing, ensuring sufficient amplification gain, thereby ensuring that the amplified signal has a higher signal-to-noise ratio, and ensuring the normal operation of the GNSS antenna and the navigation system can still receive satellite signals in a complex environment.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A GNSS antenna LNA amplifier circuit, characterized in that: It includes a first-stage amplifying circuit for satellite signals of a first frequency band, a first-stage amplifying circuit for satellite signals of a second frequency band, and a second-stage amplifying circuit. The GNSS antenna is connected to the first-stage amplifying circuit for satellite signals of the first frequency band and the first-stage amplifying circuit for satellite signals of the second frequency band. The first-stage amplifying circuit for satellite signals of the first frequency band and the first-stage amplifying circuit for satellite signals of the second frequency band are connected to the second-stage amplifying circuit. The first-stage amplifying circuit for satellite signals in the first frequency band and the first-stage amplifying circuit for satellite signals in the second frequency band both include a first-stage filter, a first-stage amplifying chip, a second-stage filter, an interstage matching resistor, an interstage matching capacitor, and an interstage matching inductor. The GNSS antenna is connected to the input end of the first-stage filter, the output end of the first-stage filter is connected to the interstage matching resistor, the interstage matching resistor is connected in series with the interstage matching capacitor, the interstage matching capacitor is connected to the input end of the first-stage amplifying chip, one end of the interstage matching inductor is connected between the interstage matching resistor and the interstage matching capacitor, the other end of the interstage matching inductor is grounded, the output end of the first-stage amplifying chip is connected to the input end of the second-stage filter, and the output end of the second-stage filter is connected to the second-stage amplifying circuit; The second-stage amplifier circuit includes a second-stage amplifier chip and a third-stage amplifier chip, the second-stage filters of the first-stage amplifier circuit for satellite signals of the first frequency band and the first-stage amplifier circuit for satellite signals of the second frequency band are both connected to the input end of the second-stage amplifier chip, and the output end of the second-stage amplifier chip is connected to the input end of the third-stage amplifier chip; The second-stage amplifier circuit also includes a first gain resistor, a second gain resistor, a third inductor, a third capacitor, a fourth inductor, a fourth capacitor, and an output matching circuit. The output matching circuit includes a fifth capacitor, a second resistor, a third resistor, a fourth resistor, and a sixth capacitor. The output end of the second-stage amplifier chip is connected to the first gain resistor, the first gain resistor is connected to the third inductor, one end of the second gain resistor is connected between the first gain resistor and the third inductor, and the other end is grounded. The third inductor is connected in series with the third capacitor, and the third capacitor is connected to the input end of the third-stage amplifier chip. One end of the fourth inductor is connected in series with one end of the fourth capacitor, and the other end of the fourth inductor is connected between the third capacitor and the input end of the third-stage amplifier chip. The other end of the fourth capacitor is grounded. The fifth capacitor, the second resistor, and the sixth capacitor are connected in series in sequence. The fifth capacitor is connected to the output end of the third-stage amplifier chip. One end of the third resistor is connected between the fifth capacitor and the second resistor, and the other end is grounded. One end of the fourth resistor is connected between the second resistor and the sixth capacitor, and the other end is grounded. The first-frequency-band satellite signal first-stage amplifier circuit and the second-frequency-band satellite signal first-stage amplifier circuit both further include a first resistor, and the GNSS antenna is connected to the input end of the first-stage filter via the first resistor.

2. A GNSS antenna LNA amplifier circuit as claimed in claim 1, characterized in that: The first-stage amplifying circuit for satellite signals of the first frequency band and the first-stage amplifying circuit for satellite signals of the second frequency band both further include a first inductor and a first capacitor. The output end of the first-stage amplifying chip is connected to a power supply through the first inductor, and the output end of the first-stage amplifying chip is connected to an input end of the second-stage filter through the first capacitor.

3. The GNSS antenna LNA amplifier circuit according to claim 1, characterized in that: The second-stage amplifier circuit also includes a second inductor and a second capacitor. The second-stage filters of the first-stage amplifier circuit for satellite signals in the first frequency band and the first-stage amplifier circuit for satellite signals in the second frequency band are both connected to the second inductor. The second inductor is connected in series with the second capacitor. The second capacitor is connected to the input end of the second-stage amplifier chip.

4. The GNSS antenna LNA amplifier circuit according to claim 1, characterized in that: The first-stage amplifying circuit for satellite signals of the first frequency band, the first-stage amplifying circuit for satellite signals of the second frequency band, and the second-stage amplifying circuit all further include a decoupling circuit, and the decoupling circuit is connected to a power supply.

5. The GNSS antenna LNA amplifier circuit according to claim 4, characterized in that: The decoupling circuit includes a first decoupling capacitor and a second decoupling capacitor, the first decoupling capacitor and the second decoupling capacitor are connected in parallel, one end of the parallel circuit of the first decoupling capacitor and the second decoupling capacitor is grounded, and the other end is connected to a power supply.

6. The GNSS antenna LNA amplifier circuit according to claim 1, characterized in that: The first-stage amplifier circuit for the satellite signal of the first frequency band is a first-stage amplifier circuit for the satellite signal of the 1.2G frequency band, the first-stage amplifier circuit for the satellite signal of the second frequency band is a first-stage amplifier circuit for the satellite signal of the 1.5G frequency band, the first-stage amplifier chip is an amplifier chip with a gain of 18dB and a noise of 0.3dB, the second-stage amplifier chip and the third-stage amplifier chip are amplifier chips with a gain of 14dB and a noise of 1dB, and the first-stage filter and the second-stage filter are dielectric filters.

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