阅读说明：本技术 一种2-18GHz的平方律检波器 (2-18GHz square law detector ) 是由 李颖 王晓青 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种2-18GHz的平方律检波器,包括输入匹配网络、检波二极管和低通滤波器,检波二极管一端连接输入匹配网络,另一端连接低通滤波器。肖特基二极管采用Skyworks的P型肖特基低势垒检波二极管SMS7630-079LF。检波器工作于零偏置状态,工作频率范围为2-18GHz,通过前级的阻抗网络匹配的后级的低通滤波器,电压灵敏度高于1500 mV/mW,实现了5GHz左右6000 mV/mW的峰值,对应的NEP优于1.49pW/Hz,带宽宽,谐波抑制度高。(The invention discloses a 2-18GHz square law detector which comprises an input matching network, a detection diode and a low-pass filter, wherein one end of the detection diode is connected with the input matching network, and the other end of the detection diode is connected with the low-pass filter. The Schottky diode adopts a P-type Schottky low-barrier detection diode SMS7630-079LF of Skyworks. The detector works in a zero offset state, the working frequency range is 2-18GHz, the voltage sensitivity is higher than 1500 mV/mW through a rear-stage low-pass filter matched with a front-stage impedance network, the peak value of 6000 mV/mW about 5GHz is realized, the corresponding NEP is better than 1.49pW/Hz, the bandwidth is wide, and the harmonic suppression degree is high.)

1. A2-18 GHz square law detector is characterized in that: comprises that

The input matching network adopts a stepping impedance transformation structure and an open-circuit short stub;

the anode of the detection diode is connected with the input matching network;

and the low-pass filter adopts a fan-shaped branch microstrip filter, and the cathode of the detection diode is connected with the low-pass filter.

2. The 2-18GHz square law detector of claim 1, wherein: the detector diode adopts a Skyworks P-type Schottky low-barrier detector diode.

3. The 2-18GHz square law detector of claim 2 wherein: the P-type Schottky low-isolation detector diode of Skyworks is in the model of SMS7630-079LF, and is connected with a resistor in seriesR _S =20 Ω, junction capacitanceC _j And the frequency of the detector is not less than 0.14pF, so that the detector still has good performance at 26G.

4. The 2-18GHz square law detector of claim 1, wherein: the dimensional parameters input to the matching network are as follows:

inputting the width of each section of the matching network: w1=2.02mm, w2=1.54mm, w3=0.57mm, w4=0.15mm,

inputting lengths of all sections of the matching network: l1=1.90mm, L2=1.23mm, L3=1.40mm, L4=0.89mm, L5=0.96 mm.

5. The 2-18GHz square law detector of claim 1, wherein: the size parameters of the low-pass filter are as follows:

four fan angles of the low pass filter: w0=70 °,

length of each section of the low-pass filter: l6=4.78mm, L7=1.75mm,

width of low-pass filter: w5=0.32 mm.

Technical Field

The invention belongs to the technical field of communication, and particularly relates to a 2-18GHz square law detector.

Technical Field

The analysis method of the Schottky detector diode can be divided into two types: one is a small signal (low input power) analysis model-square law detection mode; the other is a large signal (high input power) analysis model-the working mode of linear detection. In practice, however, the detector diode can be operated in both the small signal mode and the large signal mode. With the development of communication technology and the expansion of the application range of the detector diode, the requirements on the detector diode are higher and higher, and the dynamic range of the detector diode is required to be larger and larger. Therefore, the detection characteristics of the diode have been the focus of research.

In recent years, R.G.Hanison et al have used the Ritz-Galerkin algorithm to find the closed expression of the non-square law characteristic of the diode detector, and have analyzed the detection characteristic of the microwave diode detector. However, the presence of high frequency ripples is ignored for simplifying the derivation process, and the influence of the operating frequency on the detector characteristics is contained in the high frequency ripples, so that the influence of the high frequency ripples and the operating frequency on the detector characteristics cannot be theoretically demonstrated.

Chinese patent 201611027593.6 discloses a waveguide broadband detector, which comprises a waveguide and a detector circuit arranged in the waveguide, wherein the detector circuit comprises a fin line broadband conversion circuit, a fin line is arranged in the fin line broadband conversion circuit, a diode is arranged at the tail end of the fin line, the front end of the diode is in contact with the edge of the waveguide through a metal fin to form a direct current ground loop, and a signal reflection circuit is arranged at the position of a quarter wavelength of a detection input signal, which is a distance from the diode. Although the invention has wide working frequency band, good frequency response and high detection efficiency, the voltage sensitivity of the technology in a broadband range is not high enough, and the harmonic suppression degree is not high enough.

Disclosure of Invention

The invention aims to provide a 2-18GHz square law detector, which overcomes the defects that a broadband detector is not high enough in voltage sensitivity and harmonic suppression degree in a broadband.

The technical solution for realizing the purpose of the invention is as follows: a2-18 GHz square law detector comprises an input matching network, a detection diode and a low-pass filter, wherein one end of the detection diode is connected with the input matching network, and the other end of the detection diode is connected with the low-pass filter.

The input matching network is used as the front end of the detector, a stepped impedance transformation structure and an open-short stub are adopted, and as shown in fig. 3, the size parameters are as follows:

inputting the width of each section of the matching network: w1=2.02mm, w2=1.54mm, w3=0.57mm, w4=0.15mm,

inputting lengths of all sections of the matching network: l1=1.90mm, L2=1.23mm, L3=1.40mm, L4=0.89mm, L5=0.96 mm.

The detector diode makesSkyworks P-type Schottky low-isolation detector diode with the model number of SMS7630-079LF and series resistorR _S =20 Ω, junction capacitanceC _j =0.14pF, welded between the gap of the input matching network and the low-pass filter.

The low-pass filter adopts a high-low impedance fan-shaped branch microstrip filter as a post stage of the detector, and as shown in fig. 4, the size parameters are as follows:

four fan angles of the low pass filter: w0=70 °,

length of each section of the low-pass filter: l6=4.78mm, L7=1.75mm,

width of low-pass filter: w5=0.32 mm.

Compared with the prior art, the invention has the following remarkable advantages:

(1) the sensitivity is high: the structure of step impedance conversion and the short stub of open circuit short circuit are adopted on the input matching network, and as much input signal power as possible enters the diode.

(2) The harmonic suppression degree is high: the low-pass filter adopts a fan-shaped structure, and the suppression degree of harmonic waves is high.

(3) The reflection coefficient and the frequency band matching degree are good: further optimization of the more accurate diode simulation model and matching network will help achieve better S11 and wider band matching.

The invention is described in further detail below with reference to the figures and the detailed description.

Drawings

FIG. 1 is a schematic diagram of the structure of a 2-18GHz square law detector of the present invention.

FIG. 2 is a dimension plot of the-18 GHz square law detector of the present invention.

Fig. 3 is a schematic diagram of the structure of the input matching network of fig. 1.

Fig. 4 is a schematic diagram of the structure of the low-pass filter in fig. 1.

Fig. 5 is a measured and simulated S11 graph.

Fig. 6 is a voltage sensitivity graph.

Fig. 7 is a graph of voltage sensitivity simulations at different input powers.

Fig. 8 is a graph of output voltage simulations relating to 5GHz input power.

Detailed Description

The square law detector of 2-18GHz works in a zero bias state and comprises an input matching network 1, a detection diode 2 and a low-pass filter 3; the circuit was fabricated using a standard commercial dielectric substrate (Rogers 4350, 20mil thickness); to obtain high voltage sensitivity of the input matching network 1 of the detector, a suitable matching network must be used so that as much input signal power as possible enters the diode, and in this design, the structure of the stepped impedance transformation and the open-short stub are used as the matching network. The detector diode 2 of the detector uses a P-type Schottky low-barrier detector diode SMS7630-079LF of Skyworks, and the series resistance of the detector diodeR _S =20 Ω, junction capacitanceC _j =0.14pF, the corresponding NEP is better than 1.49pW/√ Hz; the low-pass filter 3 of the detector adopts a high-low impedance fan-shaped branch micro-strip filter, because the nonlinearity of a diode can generate rich frequency components, and the output of the detector only needs to obtain a direct current component, the LPF is vital to release direct current voltage and remove unnecessary frequency spectrum components, the low-pass filter output by the diode has good broadband radio frequency signal inhibition capability, the fan-shaped structure has good wide stop band characteristics, and the design mainly inhibits fundamental wave components and second harmonic components.

With reference to fig. 1 and 2, the 2-18GHz square law detector of the present invention includes an input matching network 1, a detector diode 2 and a low pass filter 3, wherein one end of the detector diode 2 is connected to the input matching network 1, and the other end is connected to the low pass filter 3.

The input matching network 1 is used as the front end of the detector, and adopts a stepped impedance transformation structure and an open-short stub, as shown in fig. 3, the dimensional parameters are as follows:

input matching network 1 section width: w1=2.02mm, w2=1.54mm, w3=0.57mm, w4=0.15mm,

inputting lengths of sections of the matching network 1: l1=1.90mm, L2=1.23mm, L3=1.40mm, L4=0.89mm, L5=0.96 mm.

The detector diode 2 is a P-type Schottky low-impedance detector diode of Skyworks, the model is SMS7630-079LF, and the detector diode is welded between a gap of the input matching network 1 and the low-pass filter 3.

The low-pass filter 3 adopts a high-low impedance fan-shaped branch microstrip filter as a post stage of the detector, and as shown in fig. 4, the size parameters are as follows:

four fan angles of the low-pass filter 3: w0=70 °,

length of each section of the low-pass filter 3: l6=4.78mm, L7=1.75mm,

width of low-pass filter 3: w5=0.32 mm.

Measured and simulated S11 curves as shown in fig. 5, the input matching network 1 of the present invention works well around 5GHz, and further optimization of the more accurate diode simulation model and matching network will help achieve better S11 and wider band matching.

As shown in FIG. 6, the voltage sensitivity was better than 3000 mV/mW in the frequency range of 5-10GHz, and reached a maximum voltage sensitivity of 6000 mV/mW around 5 GHz. Another key detector parameter is the equivalent noise power (NEP), which quantifies the noise level generated by the detector itself, setting a lower limit on the detectable power of the detector. Fig. 7 shows the voltage sensitivity at different input powers, with the output voltage sensitivity decreasing with increasing input power.

The output voltage associated with the 5GHz input power is shown in fig. 8. The input power must be less than-15 dBm to ensure that the detector operates in the square law region.

A 2-18GHz square law detector was designed and fabricated based on a commercial schottky diode. The test result shows that the voltage sensitivity is higher than 1500 mV/mW in the whole frequency range, the peak value of 6000 mV/mW about 5GHz is realized, and the equivalent power of the noise is 1.49 pW/Hz. By further optimizing the design, a wider band matching can be achieved and the results will be presented in the near future.