High-isolation and high-selectivity filtering power divider with input end broadband non-reflection characteristic

Abstract

The invention discloses a high-isolation and high-selectivity filtering power divider with an input end broadband non-reflection characteristic. Comprising an input port, two output ports, a double-L-shaped non-reflection absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflection absorption isolation resistors, a quarter-wavelength parallel coupling connecting line and two U-shaped transmission lines. The input port is a first port; the two output ports comprise a port II and a port III; the double-L-shaped non-reflection absorption structure comprises a first non-reflection absorption resistor, a second non-reflection absorption resistor, a first L-shaped non-reflection absorption connecting line and a second L-shaped non-reflection absorption connecting line. According to the invention, the broadband reflection-free absorption characteristic of the input end and the broadband high isolation between the output ports are realized at the same time, a plurality of transmission zeros are introduced through the L-shaped step resonators, and the frequency selectivity and out-of-band rejection are improved.

Description

Technical Field

[0001] This invention relates to a power divider filter, specifically a high-isolation, high-selectivity power divider filter with wideband, non-reflective input characteristics. Background Technology

[0002] In modern wireless communication and radar systems, the demand for multifunctional, high-performance passive devices in the radio frequency front-end is increasingly urgent, and modern communication systems are developing towards integration and miniaturization. As a key component combining frequency selection and power distribution functions, the performance of the filter power divider directly affects the system's signal integrity, anti-interference capability, and integration level. Therefore, filter power dividers with characteristics such as non-reflection, high isolation, and high selectivity are of greater research value.

[0003] Reflection-free filter power dividers are a type of microwave power divider that integrates filtering functions and reflection-free performance. Their core feature is reducing or completely eliminating the reflection of RF input signal power from the stopband region back to the signal source, while simultaneously achieving power distribution and highly selective filtering to prevent reflected signals from degrading the performance of adjacent nonlinear devices in the system. Filter power dividers with high isolation characteristics can ensure signal purity and power distribution accuracy, avoiding communication quality degradation and device damage caused by crosstalk; broadband isolation adapts to the wideband requirements of modern systems, simplifies design, and ensures stable performance across the entire frequency band.

[0004] However, traditional power dividers rely on the loss characteristics of absorption stubs for input-side reflectionlessness, and on the isolation between output ports, they depend on the isolation resistor and the characteristic impedance of the coupling line. These two parameters are mutually restrictive and difficult to balance simultaneously, making it impossible to achieve both broadband reflectionlessness and broadband high isolation. Therefore, it is indeed necessary to propose a high-isolation, high-selectivity power divider with broadband reflectionlessness at the input. Summary of the Invention

[0005] Based on this, in order to address the shortcomings of existing technologies, a high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics is proposed.

[0006] Based on the above objectives, the technical solution of the present invention is: an input port, two output ports, a double L-shaped non-reflective absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflective absorption isolation resistors, a quarter-wavelength parallel coupling connecting line, and two U-shaped transmission lines.

[0007] The input port is port one;

[0008] The two output ports include port two and port three;

[0009] The double L-shaped non-reflective absorption structure includes a first non-reflective absorption resistor, a second non-reflective absorption resistor, a first L-shaped non-reflective absorption connecting line, and a second L-shaped non-reflective absorption connecting line; wherein one end of the first non-reflective absorption resistor is connected to the first L-shaped non-reflective absorption connecting line, and the other end is connected to port one; one end of the second non-reflective absorption resistor is connected to the second L-shaped non-reflective absorption connecting line, and the other end is connected to port one; one end of the first L-shaped non-reflective absorption connecting line is connected to the first non-reflective absorption resistor, and the other end is grounded; one end of the second L-shaped non-reflective absorption connecting line is connected to the second non-reflective absorption resistor, and the other end is grounded.

[0010] The two microstrip connecting lines include a first microstrip connecting line and a second microstrip connecting line; wherein one end of the first microstrip connecting line is connected to port one and the other end is connected to port a of the first parallel coupling line; one end of the second microstrip connecting line is connected to port one and the other end is connected to port a of the second parallel coupling line.

[0011] The two parallel coupling lines include a first parallel coupling line and a second parallel coupling line; wherein the a port of the first parallel coupling line is connected to the first microstrip connection line, the b port of the first parallel coupling line is connected to the first non-reflective absorption isolation resistor, the c port of the first parallel coupling line is open, and the d port of the first parallel coupling line is connected to port two; the a port of the second parallel coupling line is connected to the second microstrip connection line, the b port of the second parallel coupling line is connected to the second non-reflective absorption isolation resistor, the c port of the second parallel coupling line is open, and the d port of the second parallel coupling line is connected to port three.

[0012] The two L-shaped step resonators include a first L-shaped step resonator and a second L-shaped step resonator; the first L-shaped step resonator includes a first step impedance line and a second step impedance line; the second L-shaped step resonator includes a third step impedance line and a fourth step impedance line; one end of the first step impedance line is connected to the connection between port d and port 2 of the first parallel coupling line, and the other end is connected to the second step impedance line; one end of the second step impedance line is connected to the first step impedance line, and the other end is open-circuited; one end of the third step impedance line is connected to the connection between port d and port 3 of the second parallel coupling line, and the other end is connected to the fourth step impedance line; one end of the fourth step impedance line is connected to the third step impedance line, and the other end is open-circuited.

[0013] The two non-reflective absorption isolation resistors include a first non-reflective absorption isolation resistor and a second non-reflective absorption isolation resistor; wherein one end of the first non-reflective absorption isolation resistor is connected to port b of the first parallel coupling line, and the other end is connected to the connection point between the e end of the quarter-wavelength parallel coupling line and the second isolation resistor; one end of the second non-reflective absorption isolation resistor is connected to port b of the second parallel coupling line, and the other end is connected to the connection point between the g end of the quarter-wavelength parallel coupling line and the first isolation resistor;

[0014] The e port and g port of the quarter-wavelength parallel coupling connection line are connected, the f port of the quarter-wavelength parallel coupling connection line is connected to the first quarter-wavelength U-shaped transmission line, and the h port of the quarter-wavelength parallel coupling connection line is connected to the second quarter-wavelength U-shaped transmission line.

[0015] The two U-shaped transmission lines include a first quarter-wavelength U-shaped transmission line and a second quarter-wavelength U-shaped transmission line; wherein one end of the first quarter-wavelength U-shaped transmission line is connected to the f port of the quarter-wavelength parallel coupling connection line and the other end is connected to the second quarter-wavelength U-shaped transmission line; one end of the second quarter-wavelength U-shaped transmission line is connected to the h port of the quarter-wavelength parallel coupling connection line and the other end is connected to the first quarter-wavelength U-shaped transmission line.

[0016] Furthermore, by adjusting the first non-reflective absorption resistor, the second non-reflective absorption resistor, the first non-reflective absorption isolation resistor, and the second non-reflective absorption isolation resistor, the non-reflective absorption characteristics and the isolation characteristics between the output ports of the filter power divider can be adjusted.

[0017] Furthermore, by adjusting the first L-shaped step resonator and the second L-shaped step resonator, the out-of-band transmission zero position of the filter power divider can be adjusted.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] To improve the isolation and selectivity of a power divider, and to extend its anti-reflection characteristics and bandwidth, this invention provides a high-isolation, high-selectivity power divider with broadband anti-reflection characteristics at the input. This power divider can be implemented on a single PCB board, facilitating fabrication and integration. Based on a coupled-line structure, the power divider achieves wideband filtering and power distribution. By introducing an improved absorption-isolation network, it simultaneously achieves broadband anti-reflection absorption characteristics at the input and broadband high isolation between the output ports. Multiple transmission zeros are introduced through an L-shaped step resonator, improving frequency selectivity and out-of-band rejection. Parameter optimization ensures optimal anti-reflection characteristics, isolation, and frequency selectivity across the wide bandwidth. This power divider meets the demands of modern radio systems for miniaturized, low-loss, and high-performance power dividers. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics according to the present invention.

[0022] Figure 2 This invention relates to a high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics. 11 and S 21 Amplitude curve;

[0023] Figure 3 This invention relates to a high-isolation, high-selectivity filter power divider S with wideband, non-reflective input characteristics. 22 and S 12 Amplitude curve;

[0024] Figure 4 This is an isolation curve of a high-isolation, high-selectivity filter power divider with wide-bandwidth, non-reflective input characteristics according to the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] like Figure 1 The high-isolation, high-selectivity filter power divider shown has broadband non-reflective characteristics at the input end, including: an input port, two output ports, a dual L-shaped non-reflective absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflective absorption isolation resistors, a quarter-wavelength parallel coupling connecting line 16, and two U-shaped transmission lines.

[0027] The input port is port 1;

[0028] The two output ports include port 2 (12) and port 3 (13);

[0029] The double L-shaped non-reflective absorption structure includes a first non-reflective absorption resistor 2, a second non-reflective absorption resistor 3, a first L-shaped non-reflective absorption connecting line 4, and a second L-shaped non-reflective absorption connecting line 5; wherein one end of the first non-reflective absorption resistor 2 is connected to the first L-shaped non-reflective absorption connecting line 4, and the other end is connected to port 1; one end of the second non-reflective absorption resistor 3 is connected to the second L-shaped non-reflective absorption connecting line 5, and the other end is connected to port 1; one end of the first L-shaped non-reflective absorption connecting line 4 is connected to the first non-reflective absorption resistor 2, and the other end is grounded; one end of the second L-shaped non-reflective absorption connecting line 5 is connected to the second non-reflective absorption resistor 3, and the other end is grounded;

[0030] The two microstrip connection lines include a first microstrip connection line 6 and a second microstrip connection line 7; wherein one end of the first microstrip connection line 6 is connected to port 1 and the other end is connected to port 1a of the first parallel coupling line 8; one end of the second microstrip connection line 7 is connected to port 1 and the other end is connected to port 2a of the second parallel coupling line 9.

[0031] The two parallel coupling lines include a first parallel coupling line 8 and a second parallel coupling line 9; wherein the a port 1a of the first parallel coupling line 8 is connected to the first microstrip connection line 6, the b port 1b of the first parallel coupling line 8 is connected to the first non-reflective absorption isolation resistor 14, the c port 1c of the first parallel coupling line 8 is open, and the d port 1d of the first parallel coupling line 8 is connected to port 12; the a port 2a of the second parallel coupling line 9 is connected to the second microstrip connection line 7, the b port 2b of the second parallel coupling line 9 is connected to the second non-reflective absorption isolation resistor 15, the c port 2c of the second parallel coupling line 9 is open, and the d port 2d of the second parallel coupling line 9 is connected to port 13.

[0032] The two L-shaped step resonators include a first L-shaped step resonator 10 and a second L-shaped step resonator 11; the first L-shaped step resonator 10 includes a first step impedance line 101 and a second step impedance line 102; the second L-shaped step resonator 11 includes a third step impedance line 111 and a fourth step impedance line 112; one end of the first step impedance line 101 is connected to the connection between port 1d and port 12 of the first parallel coupling line 8, and the other end is connected to the second step impedance line 102; one end of the second step impedance line 102 is connected to the first step impedance line 101, and the other end is open; one end of the third step impedance line 111 is connected to the connection between port 2d and port 13 of the second parallel coupling line 9, and the other end is connected to the fourth step impedance line 112; one end of the fourth step impedance line 112 is connected to the third step impedance line 111, and the other end is open.

[0033] The two non-reflective absorption isolation resistors include a first non-reflective absorption isolation resistor 14 and a second non-reflective absorption isolation resistor 15; wherein one end of the first non-reflective absorption isolation resistor 14 is connected to port 1b of the first parallel coupling line 8, and the other end is connected to the connection point between the e end 1e of the quarter-wavelength parallel coupling connection line 16 and the second isolation resistor 15; one end of the second non-reflective absorption isolation resistor 15 is connected to port 2b of the second parallel coupling line 9, and the other end is connected to the connection point between the g end 1g of the quarter-wavelength parallel coupling connection line 16 and the first isolation resistor 14;

[0034] The e port 1e and g port 1g of the quarter-wavelength parallel coupling connection line 16 are connected, the f port 1f of the quarter-wavelength parallel coupling connection line 16 is connected to the first quarter-wavelength U-shaped transmission line 17, and the h port 1h of the quarter-wavelength parallel coupling connection line 16 is connected to the second quarter-wavelength U-shaped transmission line 18.

[0035] The two U-shaped transmission lines include a first quarter-wavelength U-shaped transmission line 17 and a second quarter-wavelength U-shaped transmission line 18; wherein one end of the first quarter-wavelength U-shaped transmission line 17 is connected to port 1f of the quarter-wavelength parallel coupling connection line 16, and the other end is connected to the second quarter-wavelength U-shaped transmission line 18; one end of the second quarter-wavelength U-shaped transmission line 18 is connected to port 1h of the quarter-wavelength parallel coupling connection line 16, and the other end is connected to the first quarter-wavelength U-shaped transmission line 17.

[0036] By adjusting the first non-reflective absorption resistor 2, the second non-reflective absorption resistor 3, the first non-reflective absorption isolation resistor 14, and the second non-reflective absorption isolation resistor 15, the non-reflective absorption characteristics and the isolation characteristics between the output ports of the filter power divider can be adjusted.

[0037] The out-of-band transmission zero position of the filter power divider is adjusted by adjusting the first L-shaped step resonator 10 and the second L-shaped step resonator 11.

[0038] To further illustrate the high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics provided by this invention, specific examples of implementation based on the technical solution of this invention are described in detail below. However, the scope of protection of this invention is not limited to the following embodiments, and the methods used in the following embodiments are conventional methods unless otherwise specified.

[0039] Specific Example: This example illustrates a high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics. For example... Figure 2 As shown, the high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics described in this invention has an insertion loss of 3.41 dB at a center frequency of 2.45 GHz, a 3 dB relative bandwidth of 49.4%, and a filter reflection coefficient |S 11 The out-of-band rejection is less than -10dB in the frequency range of 0.1–6.91 GHz. Three transmission zeros are introduced outside the filter's passband at 1.38 GHz, 3.47 GHz, and 5.46 GHz, resulting in out-of-band rejection levels greater than 20dB in both the upper and lower stopbands. For example... Figure 3 As shown, the reflection coefficient |S| of a high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics described in this invention is... 22 The impedance is less than -13.6dB in the passband frequency range of 1.90–2.91GHz, exhibiting good output port impedance matching characteristics. For example... Figure 4As shown, the isolation between port 2 and port 3 of the high-isolation, high-selectivity filter power divider with wideband reflection-free input characteristics described in this invention is greater than 30 dB in the passband and greater than 20 dB across the entire 0–7 GHz frequency band. This indicates that the high-isolation, high-selectivity filter power divider with wideband reflection-free input characteristics described in this invention not only possesses high selectivity and wideband high isolation, but also exhibits excellent reflection-free absorption capability and wideband reflection-free bandwidth.

[0040] In summary, the high-isolation, high-selectivity power divider with wide-bandwidth, non-reflective input characteristics described in this invention can be implemented on a single PCB board, which is beneficial for fabrication and integration. Furthermore, this power divider not only possesses wide-bandwidth, non-reflective input characteristics, improving the stability of communication systems, but also exhibits wide-bandwidth, high-isolation output ports with strong anti-interference capabilities. Moreover, it introduces transmission zeros on both sides of the passband, enhancing the frequency selectivity of the power divider. Therefore, it is highly suitable for application in various microwave systems to improve the overall system performance.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics, characterized in that... include: Input port, two output ports, double L-shaped non-reflective absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflective absorption isolation resistors, quarter-wavelength parallel coupling connecting lines (16) and two U-shaped transmission lines; The input port is port one (1); The two output ports include port two (12) and port three (13); The double L-shaped non-reflective absorption structure includes a first non-reflective absorption resistor (2), a second non-reflective absorption resistor (3), a first L-shaped non-reflective absorption connecting line (4), and a second L-shaped non-reflective absorption connecting line (5); wherein one end of the first non-reflective absorption resistor (2) is connected to the first L-shaped non-reflective absorption connecting line (4), and the other end is connected to port one (1); one end of the second non-reflective absorption resistor (3) is connected to the second L-shaped non-reflective absorption connecting line (5), and the other end is connected to port one (1); one end of the first L-shaped non-reflective absorption connecting line (4) is connected to the first non-reflective absorption resistor (2), and the other end is grounded; one end of the second L-shaped non-reflective absorption connecting line (5) is connected to the second non-reflective absorption resistor (3), and the other end is grounded; The two microstrip connection lines include a first microstrip connection line (6) and a second microstrip connection line (7); wherein one end of the first microstrip connection line (6) is connected to port one (1) and the other end is connected to port a (1a) of the first parallel coupling line (8); one end of the second microstrip connection line (7) is connected to port one (1) and the other end is connected to port a (2a) of the second parallel coupling line (9); The two parallel coupling lines include a first parallel coupling line (8) and a second parallel coupling line (9); wherein the a port (1a) of the first parallel coupling line (8) is connected to the first microstrip connection line (6), the b port (1b) of the first parallel coupling line (8) is connected to the first non-reflective absorption isolation resistor (14), the c port (1c) of the first parallel coupling line (8) is open, and the d port (1d) of the first parallel coupling line (8) is connected to port two (12); the a port (2a) of the second parallel coupling line (9) is connected to the second microstrip connection line (7), the b port (2b) of the second parallel coupling line (9) is connected to the second non-reflective absorption isolation resistor (15), the c port (2c) of the second parallel coupling line (9) is open, and the d port (2d) of the second parallel coupling line (9) is connected to port three (13); The two L-shaped step resonators include a first L-shaped step resonator (10) and a second L-shaped step resonator (11); the first L-shaped step resonator (10) includes a first step impedance line (101) and a second step impedance line (102); the second L-shaped step resonator (11) includes a third step impedance line (111) and a fourth step impedance line (112); one end of the first step impedance line (101) is connected to port d (1d) and port 2 (12) of the first parallel coupling line (8). The connection point is connected to the second step impedance line (102) at the other end; one end of the second step impedance line (102) is connected to the first step impedance line (101) at one end and the other end is open; one end of the third step impedance line (111) is connected to the connection point between port d (2d) and port three (13) of the second parallel coupling line (9) at one end and the other end is connected to the fourth step impedance line (112); one end of the fourth step impedance line (112) is connected to the third step impedance line (111) at one end and the other end is open; The two non-reflective absorption isolation resistors include a first non-reflective absorption isolation resistor (14) and a second non-reflective absorption isolation resistor (15); wherein one end of the first non-reflective absorption isolation resistor (14) is connected to the b port (1b) of the first parallel coupling line (8), and the other end is connected to the e end (1e) of the quarter-wavelength parallel coupling connection line (16) and the connection point of the second isolation resistor (15); one end of the second non-reflective absorption isolation resistor (15) is connected to the b port (2b) of the second parallel coupling line (9), and the other end is connected to the g end (1g) of the quarter-wavelength parallel coupling connection line (16) and the connection point of the first isolation resistor (14); The e port (1e) and g port (1g) of the quarter-wavelength parallel coupling connection line (16) are connected, the f port (1f) of the quarter-wavelength parallel coupling connection line (16) is connected to the first quarter-wavelength U-shaped transmission line (17), and the h port (1h) of the quarter-wavelength parallel coupling connection line (16) is connected to the second quarter-wavelength U-shaped transmission line (18). The two U-shaped transmission lines include a first quarter-wavelength U-shaped transmission line (17) and a second quarter-wavelength U-shaped transmission line (18); wherein one end of the first quarter-wavelength U-shaped transmission line (17) is connected to the f port (1f) of the quarter-wavelength parallel coupling connection line (16), and the other end is connected to the second quarter-wavelength U-shaped transmission line (18); one end of the second quarter-wavelength U-shaped transmission line (18) is connected to the h port (1h) of the quarter-wavelength parallel coupling connection line (16), and the other end is connected to the first quarter-wavelength U-shaped transmission line (17).

2. The high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics according to claim 1, characterized in that: By adjusting the first non-reflective absorption resistor (2), the second non-reflective absorption resistor (3), the first non-reflective absorption isolation resistor (14), and the second non-reflective absorption isolation resistor (15), the non-reflective absorption characteristics and the isolation characteristics between the output ports of the filter power divider can be adjusted.

3. A high-isolation, high-selectivity filter power divider with wideband, non-reflective input characteristics as described in claim 1, characterized in that: The out-of-band transmission zero position of the filter power divider is adjusted by adjusting the first L-shaped step resonator (10) and the second L-shaped step resonator (11).

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