An improved wilkinson power divider

Abstract

The application relates to an improved Wilkinson power divider, which comprises an input branch and two output branches; one end of the input branch is connected with an input port, the other end of the input branch is connected with one end of the two output branches respectively, the other ends of the two output branches are connected with an output port respectively, an input matching network is connected on the input branch, a filter network and an output matching network are connected on the output branch, and an isolation branch is connected between the two output branches; the isolation branch comprises an isolation resistor and two compensation inductors, and the two compensation inductors are connected at two ends of the isolation resistor respectively. The inductive reactance generated by the compensation inductor can offset the capacitive reactance in the odd mode circuit, meanwhile, the isolation inductor and the output inductor adopt the same direction coupling design, the negative inductance effect is realized in the odd mode circuit to further weaken the capacitive reactance, and finally the reactance mismatch in the odd mode circuit is eliminated, so that the output port reaches the ideal matching state.

Description

Technical Field

[0001] This invention relates to the field of microwave radio frequency devices, and more particularly to an improved Wilkinson power divider. Background Technology

[0002] Wilkinson power dividers are critical passive components in microwave RF systems. To meet the demands of high integration, high-pass topologies based on lumped-parameter elements (inductors and capacitors) are widely adopted due to their compact size. However, rigorous parity-mode analysis of these topologies reveals an inherent odd-mode impedance mismatch mechanism. Specifically, in traditional high-pass Wilkinson structures, when the circuit is in odd-mode excitation (i.e., equal-amplitude, inverted signals are applied to both output ports), the input port is virtually grounded. In this case, the equivalent input impedance from the output port to the isolated branch is not an ideal pure resistance, but rather a net capacitive reactance component dominated by the series capacitor (i.e., a negative resistance value).

[0003] Traditional isolation branches, consisting only of pure resistors, lack a corresponding inductive component to offset the net capacitive reactance, leading to the following technical problems: Non-zero odd-mode reflection coefficient: Due to the non-zero imaginary part of the equivalent load impedance, the odd-mode reflection coefficient cannot be zeroed. Deteriorated port matching: Odd-mode reflection directly translates into worsened return loss at the output port, limiting the performance degradation of the voltage standing wave ratio (VSWR) and preventing the achievement of theoretically ideal matching. Limited isolation: Unabsorbed odd-mode energy forms coupling leakage between ports, restricting the theoretical limit of port isolation. Existing technologies typically employ compromise designs by optimizing the inductor and capacitor parameters of the main arm, but this often comes at the cost of sacrificing port return or other performance aspects and cannot fundamentally eliminate the reactive component in the odd-mode loop. Therefore, how to achieve a purely resistive transformation of the odd-mode equivalent impedance while maintaining the advantages of high-pass topology is a pressing technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an improved Wilkinson power divider, which solves the deficiencies of the prior art.

[0005] The objective of this invention is achieved through the following technical solution: an improved Wilkinson power divider, comprising an input branch and two output branches; one end of the input branch is connected to an input port, the other end of the input branch is connected to one end of each of the two output branches, the other ends of each of the two output branches are connected to an output port, an input matching network is connected to the input branch, a filter network and an output matching network are connected to the output branches, and an isolation branch is connected between the two output branches; The isolation branch includes an isolation resistor and two compensation inductors, which are respectively connected to the two ends of the isolation resistor.

[0006] The input matching network includes a high-order matching structure composed of inductors L1, L2, L3, and capacitors C1 and C2, which realizes input impedance bandwidth matching. The inductors L1 and L3 are connected in series with the input port. One end of the inductor L2 is connected between the inductors L1 and L3, and the other end is grounded. One end of the capacitor C1 is connected to the input port and the other end is grounded. One end of the capacitor C2 is connected to the inductor L3 and the other end is grounded. Inductor L3 is the output inductor, and inductor L2 is the compensation inductor. The two are coupled in the same direction and provide inductive impedance at the same time.

[0007] The filtering network includes a capacitor connected to the output branch, with one end of the capacitor connected to inductor L3 and the other end connected to the output matching network.

[0008] The output matching network includes an inductor connected to the output branch, with one end of the inductor connected to capacitor C3 and the other end connected to the output port.

[0009] The present invention has the following advantages: 1. Eliminate impedance and achieve ideal port matching: The inductive reactance generated by the compensation inductor can cancel the capacitive reactance in the odd-mode circuit, so that the equivalent impedance changes from a complex number to a pure real number and accurately matches the characteristic impedance of the port. At the same time, the isolation inductor and the output inductor adopt the same-direction coupling design, realize the negative inductance effect in the odd-mode circuit to further weaken the capacitive reactance. The two effects work together to finally eliminate the reactance mismatch in the odd-mode circuit, so that the output port reaches the ideal matching state.

[0010] 2. Achieving Ultra-Wideband Design by Combining High-Order Input Matching Networks: A high-order input matching network topology was adopted. This network structure effectively broadened the impedance matching bandwidth of the system, overcoming the limitations of traditional single-frequency or low-order matching, thus successfully achieving the ultra-wideband (UWB) design goal. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the circuit structure of the present invention.

[0012] Figure 2 This is a schematic diagram of the topological odd-mode equivalent circuit of the present invention.

[0013] Figure 3 The image shows the ADS simulation results for the traditional topology.

[0014] Figure 4 The figure shows the ADS simulation results of the topology of this invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of this application provided below with reference to the accompanying drawings is not intended to limit the scope of protection of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The present invention will be further described below with reference to the accompanying drawings.

[0016] This invention specifically relates to an improved Wilkinson power divider, which aims to solve the problem that existing high-pass Wilkinson power dividers, under odd-mode excitation, suffer from port matching deviations from ideal values ​​and limited isolation due to the presence of net capacitive reactance components in the equivalent load.

[0017] like Figure 1 As shown, it includes an input port (Port1), a first output port (Port2), a second output port (Port3), an input matching network, a high-pass filter arm network connecting the input and output, an isolation branch connecting the two output ports, and an output matching network.

[0018] Furthermore, the isolation branch is formed by connecting the isolation resistor R in series with the compensation inductors L4 and L6, and the output matching network is formed by the output inductors L5 and L7. The output inductor L3 is coupled in the same direction with the compensation inductor L2 and simultaneously provides inductive impedance. The inductors L1, L2, and L3, and the capacitors C1 and C2 together form a high-order matching structure to achieve wideband input impedance matching.

[0019] The high-pass filter arm network includes capacitor C3 connected between inductor L5 and capacitor C2, and capacitor C4 connected between inductor L7 and capacitor C2.

[0020] Furthermore, based on ADS software, a simulation comparison is performed between the traditional topology with a characteristic impedance of 50Ω and the improved topology of this invention.

[0021] like Figure 2 As shown, the circuit parameters are optimized, and the optimal component values ​​for the two topologies are as follows: Traditional topology: L1=127pH, C1=47fF, R=73Ω.

[0022] The topology of this invention is: L1=74pH, L2=72pH, L3=0.5pH, L4 and L6=125pH, L5 and L7=96pH, k=0.56, C1=58fF, C2=142fF, C3 and C4=92fF, R=120 Ω.

[0023] like Figure 3 and Figure 4 As shown, in the traditional topology, the output ports do not form an ideal match, resulting in poor port VSWR (-12dB), limited isolation performance (-12dB), and narrow bandwidth (50GHz-75GHz, relative bandwidth 40%).

[0024] The topology of this invention exhibits distinct reflection zeros at both the input and output ports, achieving ideal matching. Simulation results show that the port return loss and isolation are better than -20 dB in the 40-90 GHz range, enabling a wider bandwidth design (40 GHz-90 GHz, relative bandwidth 77%).

[0025] Therefore, simulation data confirms that the present invention effectively solves the mismatch problem of the traditional structure by introducing a compensating inductor and co-optimizing parameters, and significantly improves the matching performance and isolation of the power divider.

[0026] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and improvements, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An improved Wilkinson power divider, characterized in that: It includes an input branch and two output branches; one end of the input branch is connected to an input port, and the other end of the input branch is connected to one end of each of the two output branches. The other ends of each of the two output branches are connected to an output port. An input matching network is connected to the input branch, and a filter network and an output matching network are connected to the output branches. An isolation branch is connected between the two output branches. The isolation branch includes an isolation resistor and two compensation inductors, which are respectively connected to the two ends of the isolation resistor.

2. The improved Wilkinson power divider according to claim 1, characterized in that: The input matching network includes a high-order matching structure composed of inductors L1, L2, L3, and capacitors C1 and C2, which realizes input impedance bandwidth matching. The inductors L1 and L3 are connected in series with the input port. One end of the inductor L2 is connected between the inductors L1 and L3, and the other end is grounded. One end of the capacitor C1 is connected to the input port and the other end is grounded. One end of the capacitor C2 is connected to the inductor L3 and the other end is grounded. Inductor L3 is the output inductor, and inductor L2 is the compensation inductor. The two are coupled in the same direction and provide inductive impedance at the same time.

3. An improved Wilkinson power divider according to claim 2, characterized in that: The filtering network includes a capacitor connected to the output branch, with one end of the capacitor connected to inductor L3 and the other end connected to the output matching network.

4. An improved Wilkinson power divider according to claim 3, characterized in that: The output matching network includes an inductor connected to the output branch, with one end of the inductor connected to capacitor C3 and the other end connected to the output port.

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