Low-power-consumption broadband reflection amplification circuit suitable for environment signals

Abstract

A low-power-consumption broadband reflection amplification circuit suitable for environmental signals belongs to the field of microwave circuit design, can reflect and amplify weak signals in the environment, and can carry real-time sensing information for remote communication. Comprising a tunnel diode, a broadband filtering matching network, a radio frequency blocking device and a biasing circuit, wherein the tunnel diode is respectively connected with the broadband filtering matching network and the biasing circuit. Compared with an existing reflection amplification circuit, the problem that the power consumption of the amplification circuit is large can be solved through the tunneling effect of the tunnel diode, and the power consumption is limited within 1 mW. Different from a conventional narrowband reflection amplification circuit, the broadband low-pass broadband reflection amplification circuit provides an impedance matching network with a wide enough frequency band for a backscattering amplification circuit by using a high-order low-pass topology, and realizes weak signal amplification at a wide frequency band. The working frequency band of the low-power-consumption broadband backscattering amplification circuit provided by the invention is 550MHz-950MHz, and the relative bandwidth is 53.3%. The method has very strong market potential in the future application of the Internet of Things.

Description

Technical Field

[0001] The invention belongs to the field of microwave circuit design and relates to a low-power consumption, wide-band reflection amplifier circuit suitable for environmental signals. Background Art

[0002] In recent years, the Internet of Things technology has been able to connect sensors, devices and systems scattered everywhere to realize real-time data collection, transmission and processing. It has broad application scenarios in smart homes, smart cities, industrial Internet of Things, medical health and logistics management. In the Internet of Things scenario, Radio Frequency Identification (RFID) technology has many advantages over other technologies. For example, compared with Bluetooth and WiFi, RFID technology has lower energy consumption and lower cost, and is suitable for large-scale object identification applications. Compared with NFC technology, it has a longer reading distance and a wider range of applications. Compared with barcodes and QR codes, it has faster reading speed, larger data capacity, supports batch reading, and is not easily damaged.

[0003] Backscatter communication technology is widely used in passive RFID systems. During the communication process, the reader transmits an RF signal to the tag. While transmitting information, the RF signal also provides energy to the tag. The tag uses the received energy to activate the internal circuit and modulate the electromagnetic wave for backscatter communication. However, in traditional backscatter communication applications, the reader needs to play the role of both RF signal source and receiver, which may cause self-interference of the signal during transmission. Secondly, traditional backscatter communication applications can only passively transmit data when the reader queries. In addition, the transmission distance of traditional backscatter communication is greatly limited, which seriously restricts its application scenarios.

[0004] Backscatter communication technology suitable for environmental signals can effectively overcome the above limitations of traditional backscatter communication applications. It can effectively transmit sensor signals to receivers by modulating and reflecting radio frequency signals in the environment, thereby realizing wireless transmission of sensor information. However, existing backscatter circuits suitable for weak environmental signals generally operate at a fixed frequency. Due to the very small input power, the transmission distance is very limited, and it does not have the ability to transmit real-time sensor information. How to achieve low-power reflection amplification of environmental signals with wide-band characteristics to meet multi-scenario applications is a key problem that needs to be solved in realizing real-time communication of sensor information through environmental signals. Its realization has broad application scenarios and market promotion potential. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a low-power broadband amplifier circuit suitable for environmental signals, which is an extremely low-power broadband reflection amplifier circuit suitable for weak signals in the environment. Compared with the previous reflection amplifier circuit, the amplifier circuit utilizes the tunneling effect of the tunnel diode, which exhibits a negative differential resistance effect under a certain DC voltage bias, solves the problem of high power consumption of the amplifier circuit, and limits the power consumption to less than 1mW. Different from the previous narrow-band reflection amplifier circuit and the single-frequency reflection amplifier circuit, the present invention realizes a broadband impedance matching network by using a high-order low-pass topology. The low-power broadband backscatter amplifier circuit of the present invention is simulated and tested, and the experimental results show that the operating frequency band of the amplifier circuit is 550MHz-950MHz, and the relative bandwidth can reach 53.3%. When the input signal of the proposed amplifier circuit is -50dBm, only 0.48mW of power consumption can achieve an amplification effect of more than 24dB in the entire working frequency band, and the gain flatness is ±1dB. The circuit design proposed by the present invention has broad application potential in future Internet of Things applications.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A low-power broadband reflection amplifier circuit suitable for environmental signals, the low-power broadband reflection amplifier circuit comprising a tunnel diode, a broadband filter matching network, a radio frequency DC block and a bias circuit, the tunnel diode being connected to the broadband filter matching network and the bias circuit respectively. After the radio frequency signal enters the low-power broadband reflection amplifier circuit from the antenna, it flows into the tunnel diode after passing through the radio frequency DC block and the broadband filter matching network in sequence, the signal is reflected and amplified after passing through the tunnel diode, and the reflected and amplified signal then enters the antenna through the broadband filter matching network and the radio frequency DC block in sequence to achieve longer-distance information transmission, and the DC current provided by the DC power supply provides a suitable bias voltage for the tunnel diode after passing through the bias circuit.

[0008] The tunnel diode replaces the transistor in the traditional reflection amplifier circuit, and its function is to achieve the amplification effect through its negative differential resistance effect. The PN junction doping concentration of the tunnel diode is very high, and a very narrow depletion layer and a very high built-in electric field are formed near the PN junction. When a certain bias voltage is applied, the current at both ends of the tunnel diode will decrease as the bias voltage increases, showing a negative differential resistance effect. At the same time, the power consumption of the tunnel diode is extremely low, and it is suitable for use as a low-power broadband backscatter amplifier circuit.

[0009] The broadband filter matching network is connected to the RF isolator and the tunnel diode respectively. The broadband filter matching network is designed using a high-order low-pass topology and is used to match the impedance of the amplifier circuit to the RF source impedance of 50Ω. Taking into account the difficulty in obtaining high-precision capacitors and inductors, and taking into account the impact of the self-resonance of inductors and capacitors in broadband high-frequency scenarios, in the present invention, the capacitors and inductors in the equivalent filter matcher are connected in series in sequence with high-characteristic impedance microstrip lines and low-characteristic impedance microstrip lines, wherein high-characteristic impedance microstrip line equivalent inductors and low-characteristic impedance microstrip line equivalent capacitors are used. Specifically, the broadband filter matching network contains 8 microstrip lines, including 4 high-characteristic impedance microstrip lines and 4 low-characteristic impedance microstrip lines, and the high-characteristic impedance microstrip lines and the low-characteristic impedance microstrip lines are alternately connected in series to achieve a good matching effect.

[0010] The bias circuit is connected to the tunnel diode and the DC power supply respectively. After the DC power supply is connected in parallel with the bypass capacitor, a quarter-wavelength fan-shaped structure and a quarter-wavelength high characteristic impedance microstrip line are connected in series in sequence. By using a DC power supply, the tunnel diode is operated at a suitable static operating point. The bypass capacitor is connected in parallel between the power supply and the ground. The high-frequency interference signal will preferentially flow to the ground through the bypass capacitor instead of continuing to propagate along the bias circuit, so that the high-frequency interference on the power supply line is effectively suppressed, providing a relatively pure DC power supply for the tunnel diode. The quarter-wavelength fan-shaped structure and the quarter-wavelength high characteristic impedance microstrip line connected in series use the impedance transformation characteristics of the quarter-wavelength transmission line to effectively suppress the radio frequency signal, thereby realizing the isolation of the DC path and the radio frequency path.

[0011] The radio frequency DC block is connected to the external antenna and the broadband filter matching network respectively. The radio frequency DC block is composed of a DC blocking capacitor, which is connected in series between the antenna and the broadband filter matching network, effectively blocking the DC signal outside the DC block, thereby protecting the antenna from the harm of the DC signal and ensuring that the radio frequency signal is smoothly transmitted to the antenna for transmission.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The present invention is based on tunnel diodes, and uses the negative resistance characteristics of tunnel diodes under a certain bias voltage and their own low power consumption characteristics to complete the design of the backscattering amplifier. When the input signal is -50dBm, the proposed amplifier circuit can achieve an amplification effect of more than 24dB in the entire operating frequency band with only 0.48mW of power consumption, and the gain flatness is ±1dB. Compared with the existing reflection amplifier, it can maintain a high gain amplification effect at extremely low power consumption.

[0014] (2) The present invention uses a high-order low-pass topology to design a broadband filter matching network, ensuring that the backscatter tag can receive environmental signals of different frequency bands for communication, and is suitable for scene applications in different frequency bands. The present invention uses the characteristics of high-order filter wideband and high stopband attenuation to achieve broadband reflection amplification. Experimental results show that the operating frequency band of the amplifier circuit is 550MHz to 950MHz, and the relative bandwidth reaches 53.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural block diagram of a low-power wide-band amplifier circuit suitable for environmental signals proposed by the present invention.

[0016] Figure 2 This is a circuit schematic diagram of the amplifier circuit proposed by the present invention.

[0017] Figure 3 This is a gain data diagram of the amplifier circuit proposed in the present invention. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention is described in detail below in conjunction with the technical scheme and the accompanying drawings.

[0019] The structure diagram of the low-power broadband backscatter amplifier circuit designed by the present invention for environmental signals is shown in FIG. Figure 1 As shown, it includes a tunnel diode, a broadband filter matching network, a radio frequency DC block and a bias circuit.

[0020] The tunnel diode described in this example is connected to a broadband filter matching network and a bias circuit respectively. The tunnel diode forms a very narrow depletion layer near the PN junction, and can exhibit a negative differential resistance characteristic under a certain bias voltage, that is, as the bias voltage increases, the current decreases, so that the reflection coefficient of the circuit can be greater than 1, and it has the characteristics of low power consumption and high gain. This example uses a tunnel diode model AI301A as an amplifier device, and the negative differential resistance area is 103mV-508mV. The bias voltage of the circuit is 190.1mV, the current is 2.5mA, and the circuit bias power consumption is 0.48mW.

[0021] The front end of the broadband filter matching network is connected to the RF DC block, and the back end is connected to the tunnel diode. The high characteristic impedance microstrip line and the low characteristic impedance microstrip line are connected in series in sequence to realize the function of broadband filter matching. The broadband filter matching network adopts a high-order low-pass topology and is converted from a fourth-order Chebyshev filter matching network. Specifically, the matching network contains 8 microstrip lines, including 4 high characteristic impedance microstrip lines and 4 low characteristic impedance microstrip lines. The higher the characteristic impedance of the microstrip line, the narrower its width. Alternately connect the high characteristic impedance microstrip line and the low characteristic impedance microstrip line in series to achieve a good matching effect.

[0022] The radio frequency DC block is connected to the external antenna and the broadband filter matching network respectively. The radio frequency DC block is composed of a DC blocking capacitor, which is connected in series between the antenna and the broadband filter matching network, effectively blocking the DC signal outside the DC block, thereby protecting the antenna from the harm of the DC signal and ensuring that the radio frequency signal is smoothly transmitted to the antenna for transmission.

[0023] The front end of the bias circuit is connected to the tunnel diode, and the back end is connected to a DC power supply. The DC power supply is connected in parallel with the bypass capacitor, and then a quarter-wavelength fan-shaped structure and a quarter-wavelength high characteristic impedance microstrip line are connected in series in sequence. The appropriate static operating point of AI301A is determined by measuring the IV characteristic curve of the tunnel diode, and a DC power supply is used to provide a suitable bias voltage for AI301A. The bypass capacitor is connected in parallel between the power supply and the ground, and the high-frequency interference signal will preferentially flow to the ground through the bypass capacitor instead of continuing to propagate along the bias circuit, so that the high-frequency interference on the power supply line is effectively suppressed, providing a relatively pure DC power supply for the tunnel diode. The quarter-wavelength fan-shaped structure and the quarter-wavelength high characteristic impedance microstrip line connected in series use the impedance transformation characteristics of the quarter-wavelength structure to effectively suppress the radio frequency signal, thereby realizing the isolation of the DC path and the radio frequency path.

[0024] The principle diagram of the amplifier circuit involved in the present invention is as follows Figure 2 As shown, TL represents a microstrip line and Stub represents a fan-shaped structure microstrip line.

[0025] The tunnel diode described in this example is connected to a broadband filter matching network and a bias network, respectively. The positive electrode of the tunnel diode is connected to the bias network and the broadband filter matching network at the same time, wherein the bias network provides a suitable bias voltage for the tunnel diode; the RF signal flows into the tunnel diode through the broadband filter matching network, and after being reflected and amplified by the tunnel diode, it flows into the broadband filter matching network, and the negative electrode of the tunnel diode is grounded. The tunnel diode can achieve high-gain amplification effect under low power consumption conditions. This example uses a tunnel diode model AI301A as an amplifier device, and the negative differential resistance area is 103mV-508mV. The bias voltage of the circuit is 190.1mV, the current is 2.5mA, and the circuit bias power consumption is 0.48mW.

[0026] The front end of the broadband filter matching network is connected to the RF DC block, and the rear end is connected to the tunnel diode. The high characteristic impedance microstrip line and the low characteristic impedance microstrip line are connected in series in sequence to realize the function of broadband filter matching. The broadband filter matching network adopts a high-order low-pass topology and is converted from a fourth-order Chebyshev filter matching network. Specifically, the matching network contains 8 microstrip lines, including 4 high characteristic impedance microstrip lines and 4 low characteristic impedance microstrip lines. The higher the characteristic impedance of the microstrip line, the lower its width. The broadband filter matching network is composed of a first microstrip line 1, a second microstrip line 2, a third microstrip line 3, a fourth microstrip line 4, a fifth microstrip line 5, a sixth microstrip line 6, a seventh microstrip line 7 and an eighth microstrip line 8 connected in series in sequence. Among them, the first microstrip line 1, the third microstrip line 3, the fifth microstrip line 5, and the seventh microstrip line 7 are low characteristic impedance microstrip lines, which are characterized by a wide width of the microstrip lines; the second microstrip line 2, the fourth microstrip line 4, the sixth microstrip line 6, and the eighth microstrip line 8 are high characteristic impedance microstrip lines, which are characterized by a narrow width. After the 8 microstrip lines are alternately connected in series, the first microstrip line 1 is connected in series with a radio frequency DC block, and the eighth microstrip line 8 is connected in series with a tunnel diode.

[0027] The front end of the RF DC block is connected to an external antenna, and the rear end is connected to a broadband filter matching network. The RF DC block is implemented by a DC blocking capacitor C1. The DC blocking capacitor C1 is connected in series between the antenna and the broadband filter matching network, effectively blocking the DC signal outside the DC block, which not only protects the antenna from the harm of the DC signal, but also ensures that the RF signal is smoothly transmitted to the antenna for transmission.

[0028] The bias circuit is connected to the tunnel diode and the DC power supply respectively. The bias circuit includes a ninth microstrip line 9, a first fan-shaped structure microstrip line 1, a second fan-shaped structure microstrip line 2 and a bypass capacitor C2. The DC power supply is first connected in parallel with the bypass capacitor C2, and then the first fan-shaped structure microstrip line 1 and the second fan-shaped structure microstrip line 2 are connected in series at the same time, and then the tunnel diode is connected through the ninth microstrip line 9. The bypass capacitor C2 is connected in parallel between the power supply and the ground, and the high-frequency interference signal will preferentially flow to the ground through the bypass capacitor, so that the high-frequency interference in the circuit is effectively suppressed. The radius of the fan-shaped structure is a quarter wavelength, and the length of the ninth microstrip line 9 is also a quarter wavelength. The impedance transformation characteristics of the quarter-wavelength transmission line are used to effectively suppress the radio frequency signal, and the isolation of the DC path and the radio frequency path is achieved.

[0029] Figure 3 This is a reflection gain data diagram of a low-power wide-band amplifier circuit suitable for environmental signals proposed by the present invention. When the input signal is -50dBm, the proposed amplifier circuit can achieve an amplification effect of more than 24dB in the entire working frequency band with only 0.48mW of power consumption, and the gain flatness is ±1dB.

[0030] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A low-power, wide-band reflection amplifier circuit suitable for environmental signals, characterized in that: The low-power consumption wide-band reflection amplifier circuit comprises a tunnel diode, a broadband filter matching network, a radio frequency DC block and a bias circuit, wherein the tunnel diode is connected to the broadband filter matching network and the bias circuit respectively; After the RF signal enters the low-power consumption wide-band reflection amplifier circuit from the antenna, it flows into the tunnel diode after passing through the RF DC block and the broadband filter matching network in sequence. The signal is reflected and amplified after passing through the tunnel diode. The reflected and amplified signal then enters the antenna through the broadband filter matching network and the RF DC block in sequence to achieve information transmission over longer distances. The DC current provided by the DC power supply provides a suitable bias voltage for the tunnel diode after passing through the bias circuit.

2. A low-power, wide-band reflection amplifier circuit suitable for environmental signals according to claim 1, characterized in that: The broadband filter matching network is connected to the radio frequency DC block and the tunnel diode respectively; the broadband filter matching network is designed using a high-order low-pass topology and is used to match the impedance of the amplifier circuit to the radio frequency source impedance of 50Ω.

3. A low-power, wide-band reflection amplifier circuit suitable for environmental signals according to claim 2, characterized in that: The broadband filter matching network is achieved by sequentially connecting capacitors and inductors in high characteristic impedance microstrip lines and low characteristic impedance microstrip lines in series, wherein high characteristic impedance microstrip lines are used as equivalent inductors and low characteristic impedance microstrip lines as equivalent capacitors.

4. A low-power consumption, wide-band reflection amplifier circuit suitable for environmental signals according to claim 3, characterized in that: The broadband filter matching network comprises eight sections of microstrip lines, including eight sections of high characteristic impedance microstrip lines and four sections of low characteristic impedance microstrip lines, and the high characteristic impedance microstrip lines and the low characteristic impedance microstrip lines are alternately connected in series.

5. A low-power, wide-band reflection amplifier circuit suitable for environmental signals according to claim 1, characterized in that: The bias circuit is connected to the tunnel diode and the DC power supply respectively. The DC power supply is connected in parallel with a bypass capacitor and then connected in series with a quarter-wavelength fan-shaped structure and a quarter-wavelength high characteristic impedance microstrip line.

6. A low-power, wide-band reflection amplifier circuit suitable for environmental signals according to claim 1, characterized in that: The radio frequency DC isolator is connected to the external antenna and the broadband filter matching network respectively. The radio frequency DC isolator is composed of a DC isolating capacitor which is connected in series between the antenna and the broadband filter matching network.

7. A low-power, wide-band reflection amplifier circuit suitable for environmental signals according to claim 1, characterized in that: The low-power wide-band backscatter amplifier circuit has an operating frequency band of 550 MHz to 950 MHz, a relative bandwidth of 53.3%, and can limit power consumption to less than 1 mW.

8. The low-power consumption, wide-bandwidth reflection amplifier circuit suitable for environmental signals according to claim 1, characterized in that: The low-power wide-band backscatter amplifier circuit can achieve an amplification effect of more than 24dB in the entire working frequency band with a power consumption of 0.48mW when the input signal is -50dBm, and the gain flatness is ±1dB.

Images