阅读说明：本技术 一种扇形微带线去耦电路的设计 (Design of fan-shaped microstrip line decoupling circuit ) 是由 赛景波 张繁军 吕明 于 2020-12-03 设计创作，主要内容包括：本发明设计一种扇形微带线电源去耦电路,此电路包括四个双扇形微带线结构、5段四分之一波导波长的微带线和介质基板,这种扇形微带线电源去耦电路可以用在射频芯片的直流偏置电路中,它可以防止直流偏置电路影响射频交流电路的阻抗特性,也可以将进入直流偏置电路的部分射频交流信号进行衰减。采用上述技术方案的扇形微带线去耦频率范围是0.7GHz-4GHz,具有宽带电源去耦的特点。(The invention designs a sector microstrip line power decoupling circuit, which comprises four double-sector microstrip line structures, a 5-segment microstrip line with quarter waveguide wavelength and a dielectric substrate, and can be used in a direct current bias circuit of a radio frequency chip, prevent the direct current bias circuit from influencing the impedance characteristic of a radio frequency alternating current circuit, and attenuate part of radio frequency alternating current signals entering the direct current bias circuit. The decoupling frequency range of the fan-shaped microstrip line adopting the technical scheme is 0.7GHz-4GHz, and the decoupling frequency range has the characteristic of broadband power decoupling.)

1. A sector microstrip line decoupling circuit is characterized by comprising four double-sector microstrip line structures, five sections of microstrip lines with quarter waveguide wavelengths, a defected ground and a dielectric substrate.

2. The sectored microstrip line decoupling circuit of claim 1, wherein: the radius of the double-fan-shaped microstrip line structure is one quarter of the waveguide wavelength of the electromagnetic wave corresponding to the decoupling frequency, the angle of the fan-shaped microstrip line is 89 degrees, and a four-stage double-fan-shaped power decoupling circuit is arranged.

3. The sectored microstrip line decoupling circuit of claim 1, wherein: the length of the microstrip line connected between each fan-shaped microstrip line structure is a quarter of waveguide wavelength, the width of the microstrip line is 1mm, and the microstrip line structure is provided with five sections of high-impedance microstrip lines in total.

4. The sectored microstrip line decoupling circuit of claim 1, wherein: an opening square ring is etched on the plane below the fan-shaped microstrip line to cause the partial defect of the fan-shaped microstrip line, the length of the square ring is one eighth of the wavelength of the decoupling frequency waveguide corresponding to the fan-shaped microstrip line, and the width of the square ring is 0.4 mm.

5. The sectored microstrip line decoupling circuit of claim 1, wherein: the dielectric substrate is 0.2mm in thickness, 4.6 in dielectric constant and 1 in relative permeability, an FR4 board with a loss tangent of 0.02 is adopted, the copper foil type is a low-roughness reversal-processed copper foil, the surface roughness of the copper foil is controlled within 3um, and the thickness of the copper foil is 35 um.

Technical Field

The invention belongs to the field of power supplies, and particularly relates to a sector microstrip line power decoupling circuit.

Background

The existing general radar transmitter and receiver are all together, so that the influence is caused by the fact that high-power transmitting signals enter a receiving channel through coupling to cause the receiver to be saturated, and the receiver cannot work normally.

Disclosure of Invention

The invention aims to solve the technical problem of designing a sector microstrip line power decoupling circuit.

The technical scheme adopted by the invention for solving the technical problems is as follows: a power decoupling circuit of a double-sector microstrip line comprises four double-sector microstrip line structures, 5 sections of microstrip lines with quarter waveguide wavelength, a defected ground and a dielectric substrate. The invention provides a fan-shaped microstrip line with the radius of one-quarter waveguide wavelength for realizing power decoupling, and the fan-shaped microstrip line has the advantages of wide power decoupling frequency bandwidth compared with the open-circuit stub; the narrower the width of the microstrip line connecting each fan-shaped microstrip line structure is theoretically, the better the power decoupling effect is, but the comprehensive consideration of the limited bearing capacity of the microstrip line on the large current needs to properly select the width of the microstrip line; a square hollow is formed on the ground plane below the sector line to form a band elimination filter, and the decoupling effect of the microstrip sector line power supply can be enhanced.

In fig. 1, term1 indicates a radio frequency chip power supply port, term2 indicates a power supply port, an interference signal existing in a circuit of the power supply port is coupled to the radio frequency chip power supply port through a power line, and a radio frequency alternating current signal can also be coupled to the power supply port through the power line from the radio frequency chip power supply port, so that the power decoupling network designed herein needs to perform two functions, one is to attenuate the interference signal entering the power line, and the other is to attenuate the radio frequency alternating current signal entering the power line, so the sector microstrip line power decoupling circuit provided herein needs to have a bidirectional power decoupling function. The sector microstrip line power decoupling circuit can be qualitatively analyzed from the angle of a two-port network, and an S11 characteristic curve of a radio frequency chip power port, an S22 characteristic curve of a power supply port, an S12 curve from the power supply port to the radio frequency chip power port and an S21 curve from the radio frequency chip power port to the power supply port are analyzed, S11 represents the reflection coefficient of the sector microstrip line of the radio frequency chip power port, S11 represents that the reflection coefficient of the radio frequency chip power port is very large, even if a radio frequency alternating current signal enters the microstrip sector power decoupling circuit from the radio frequency chip power port, most of the radio frequency alternating current signal is reflected back to the radio frequency chip power port, S22 represents the reflection coefficient of the sector microstrip line of the power supply port, S22 represents that the reflection coefficient of the power supply port is very large, even if an interference signal enters the microstrip sector power decoupling circuit from the power supply port, most of the interference signals are reflected back to the power supply port; s21 represents the voltage attenuation quantity of the radio frequency alternating current signal transmitted from the power supply port of the radio frequency chip to the power supply port, S12 represents the voltage attenuation quantity of the interference signal transmitted from the power supply port to the power supply port of the radio frequency chip, and the conditions required to achieve the decoupling of the broadband power supply are that S11 and S22 are large and S12 and S21 are small in the whole frequency band.

The power decoupling circuit of the sector microstrip line power supply is based on a power gain formula of any impedance of the input end and the output end of the two-port networkThe power level coupled from the rf chip power port to the power supply port can be calculated. If the radio frequency chip outputs a radio frequency alternating current signal with the power of 100mW in the frequency range of 0.7GHz-4GHz, the S parameters of the sector microstrip line power supply decoupling circuit are as follows: s12 is-80 dB, S21 is-80 dB, S11 is-1 dB and S22 is-1 dB, and the power of the radio frequency alternating current signal with 100mW coupled to the power supply port is 3.86 x 10 through calculation of a power gain formula^-8W, S12 and S21 of the two-port network of the microstrip sector line power decoupling circuit are equal, so that the power attenuation degree of interference signals coupled from a power supply port to a power port of a radio frequency chip is the same, and the sector microstrip line power decoupling circuit can play a role in bidirectional power decoupling.

The sector microstrip line power decoupling circuit adopts four double-sector microstrip line structures and 5 sections of high-resistance microstrip lines with quarter waveguide wavelength, as shown in figure 1, a first-stage power decoupling unit (Stub1), a second-stage power decoupling unit (Stub2), a third-stage power decoupling unit (Stub3) and a fourth-stage power decoupling unit (Stub4) are arranged in sequence from a power port of a radio frequency chip to a power supply port, the radius of a sector line of the first-stage power decoupling unit is 7.6mm, the radius of the sector line of the first-stage power decoupling unit is the quarter waveguide wavelength corresponding to 4.6GHz electromagnetic waves, the radius of a sector line of the second-stage power decoupling unit is 9.9mm, the radius of the sector line of the second-stage power decoupling unit is the quarter waveguide wavelength corresponding to 3.53GHz electromagnetic waves, the radius of the sector line of the third-stage power decoupling unit is 18mm, the radius of the sector line of the third-stage power decoupling unit is the quarter waveguide wavelength corresponding to 1.94GHz electromagnetic waves, it is a quarter waveguide wavelength corresponding to 1.34GHz electromagnetic wave; the length of the first section of high-resistance microstrip line TL1 is 10mm, the length of the second section of high-resistance microstrip line TL2 is 13mm, the length of the third section of high-resistance microstrip line TL3 is 16mm, the length of the fourth section of high-resistance microstrip line TL4 is 30mm, the length of the fifth section of high-resistance microstrip line TL5 is 10mm, and the width W of the five sections of high-resistance microstrip lines is 1 mm; the power decoupling frequency ranges corresponding to the radius of the fan-shaped microstrip line are different, the power decoupling frequency of the microstrip fan-shaped line with small radius is high, the power decoupling frequency of the microstrip fan-shaped line with large radius is low, the four microstrip double-fan-shaped line structures with different radius are provided, each fan-shaped structure presents broadband power decoupling characteristics in different frequency bands, and the broadband power decoupling is formed by superposing the power decoupling characteristics corresponding to the four double-fan-shaped microstrip line structures. The power decoupling action radius corresponding to the sector microstrip line with the small radius is small, so that the sector microstrip line structure with the small radius is close to the power port of the radio frequency chip, and the power decoupling action radius corresponding to the sector microstrip line with the large radius is large, so that the sector microstrip line structure with the large radius is close to the power port of the radio frequency chip.

The radius length of the double-fan-shaped microstrip line is a quarter of the waveguide wavelength, and the angle of the fan-shaped microstrip line is 89 degrees; the length of the microstrip line connected between each fan-shaped microstrip line structure is one-quarter waveguide wavelength, and the width of the microstrip line is 1 mm; the dielectric substrate has a thickness of 0.2mm, a dielectric constant of 4.6 and a relative magnetic permeability of 1, and is made of FR4 board with a loss tangent of 0.02, the copper foil type is a low-roughness reversal-processed copper foil, the surface roughness of the copper foil is controlled within 3um, and the thickness of the copper foil is 35 um.

The invention has the advantages of

(1) The four double-fan-shaped microstrip line structures are connected in series, the power supply decoupling frequency range can reach 0.7GHz-4GHz, and broadband power supply decoupling is realized. (2) The power decoupling effect of the sector microstrip line decoupling circuit can reach-64 dB in the frequency range of 0.7GHz-4GHz, and even the power decoupling in the whole frequency band of 1.1GHz-4GHz can reach-88 dB, so that the sector microstrip line can realize the broadband power decoupling.