Nine-lobe directional diagram implementation method

Abstract

The invention discloses a nine-lobe directional diagram implementation method, and belongs to the technical field of radar antenna feeders. According to the method, a multi-stage distribution network is adopted to generate needed amplitude and phase, and a one-input three-output power distribution network, a three-input three-output amplitude and phase distribution network, a one-input three-output power distribution network and a numerical control phase shifter are included. Radio-frequency signals are input, the signals are distributed and synthesized through all levels of distribution networks, and finally 27 paths of needed amplitude phases are formed and output to the uniform circular ring array antenna to achieve a nine-lobe directional diagram. And meanwhile, the nine-lobe directional diagram can rotate through the periodic change of the numerical control phase shifter, so that the 135Hz envelope amplitude modulation capability is realized. The method for generating nine-lobe directional diagram excitation through the multi-stage distribution network has the characteristics of low cost, low loss, high reliability, amplitude-phase consistency and stability and the like. The nine-lobe directional diagram passive multilevel distribution network designed by the invention can be widely applied to a navigation system.

Description

Technical Field

[0001] The invention relates to the field of array antennas. Background Art

[0002] TACAN is the abbreviation of tactical air navigation, which is an aerial short-range tactical radio polar coordinate navigation system, and is currently widely used by air forces of various countries. The nine-petal heart-shaped pattern required for the TACAN function can be understood in principle as the superposition of a 15Hz heart-shaped pattern and a 135Hz nine-petal pattern.

[0003] Generally, a nine-petal directional pattern can be formed by superimposing an omnidirectional antenna with a modulator. The signal emitted by the coordinate center antenna unit is omnidirectional, and the corresponding directional pattern is circular. After the signal passes through the modulator, the directional pattern of the signal changes from circular to nine petals. When the modulator rotates around the center antenna at a speed of 135 circles per minute, the corresponding directional pattern also changes periodically, thus generating a 135Hz envelope amplitude modulation. The reliability of the modulators used in current technical means is not high, and the accuracy and stability are average, which can no longer meet the requirements of high-precision positioning. At the same time, the omnidirectional antenna at the center of the circle can only be placed at the highest point of the mast, which is not conducive to the integration of the mast. In addition, due to the influence of the lightning rod at the highest point, the waveform of the nine-petal directional pattern is distorted, affecting the navigation performance.

[0004] Currently, there are no public reports on a nine-petal directional pattern multi-level distribution network with low loss, high integration, high reliability, and high amplitude and phase consistency. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for realizing a nine-petal pattern, which uses a one-input three-output power distribution network, a three-input three-output amplitude-phase distribution network, and a digitally controlled phase shifter. The RF signal is fed from the main port, and the signal is distributed and synthesized through the distribution networks at various levels, and finally the required 27 amplitude phases are formed and output to the array antenna to realize the nine-petal pattern.

[0006] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0007] A method for realizing a nine-petal directional pattern includes a one-input three-output power distribution network, a three-input three-output amplitude-phase distribution network, and a digitally controlled phase shifter; wherein the one-input three-output power distribution network A1 has A1_1 as an input port, and A1_2, A1_3, and A1_4 as output ports; wherein the three-input three-output amplitude-phase distribution network B1 has B1_1, B1_2, and B1_3 as input ports, which are connected to A1_2, A1_3, and A1_4, respectively, and B1_4, B1_5, B1_6 is the output port; the digitally controlled phase shifter is between A1_2 and B1_1, A1_3 and B1_2; the one-input three-output power distribution network C1, C2, C3 are connected to B1, wherein C1_1, C2_1, C2_1 are connected to B1_4, B1_5, B1_6 respectively; the one-input three-output power distribution network D1 to D9 are connected to C1, C2, C3, wherein D1 is connected to C1_2, D4 is connected to C1_3, and D7 is connected to C1_4.

[0008] Furthermore, the one-input three-output power distribution network D1 to D9 has 27 output ports in total, which are connected to 27 columns of uniform circular array antennas. The input and output ports of each level of distribution network correspond to each other one by one, and the required excitation is formed through distribution and synthesis.

[0009] Compared with the prior art methods, the present invention has the following beneficial effects:

[0010] ① The present invention adopts a passive distribution network to realize a nine-petal directional pattern, which has the characteristics of low loss, high reliability, and stable amplitude and phase consistency;

[0011] ② The present invention adopts a passive distribution network to realize the nine-petal directional pattern, which is conducive to the integrated design with the mast platform, will not be blocked by the lightning rod, and does not need to occupy the highest point position;

[0012] ③ The present invention adopts a cascaded digitally controlled phase shifter method, and the nine-petal pattern is periodically rotated by periodic changes of the phase shifter, which has the characteristics of high precision and calibrability; BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a design diagram of a one-input and three-output power distribution network in Example 1;

[0014] Figure 2 The three-input three-output amplitude and phase distribution network in Example 1;

[0015] Figure 3 The one-input three-output power distribution network in Example 1;

[0016] Figure 4 The three-input three-output power distribution network in Example 1;

[0017] Figure 5The one-input three-output power distribution network in Example 1;

[0018] Figure 6 This is the nine-petal directional pattern in Example 1.

[0019] Description of the drawings: A1_1, input port; A1_2 to A1_3 output ports; B1_1 to B1_3 input ports; B1_4 to B1_6 output ports; C1_1, input port; C1_2 to C1_4 output ports; D1_1 input port; D1_2 to D1_4 output ports; DETAILED DESCRIPTION

[0020] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings.

[0021] Example 1

[0022] A method for realizing a nine-petal directional pattern is composed of a one-input three-output power distribution network, a three-input three-output power distribution network, and a digitally controlled phase shifter.

[0023] Reference Figure 1 , one input three output power distribution network, A1_1 port is the input port, A1_2, A1_3 are output ports, A1_4, A1_5, A1_6, A1_7 are connected to matching loads. This power distribution network provides 96% of the power to the omnidirectional mode, and 4% of the power is distributed to the nine-petal mode.

[0024] Reference Figure 2 , three-input three-output amplitude-phase distribution network, B1_1, B1_2, B1_3 are input ports connected to A1_1, A1_2, A1_3, B1_4, B1_5, B1_6 are output ports. This amplitude-phase distribution network provides in-phase output, 120° phase increasing output, and 120° phase decreasing output respectively.

[0025] Reference Figure 3 , one input three output power distribution network, C1_1 is the input port connected to B1_1, C1_2, C1_3, C1_4 are output ports. This power distribution network provides equal power outputs.

[0026] Reference Figure 4 , one input three output power distribution network, D1_1 is the input port connected to C1_1, D1_2 and D1_3 are connected to matching loads, and D1_4, D1_5, and D1_6 are output ports. This power distribution network provides equal power outputs.

[0027] Reference Figure 5 ,Multi-level distribution network topology diagram, one input and twenty-seven outputs.

[0028] Reference Figure 6 , nine-petal directional diagram.

[0029] The following is a further description of the technical effects of the embodiments of the present invention in combination with simulation experiments:

[0030] 1. Simulation conditions and contents

[0031] The full-wave simulation of the nine-petal pattern implementation in Implementation Case 1 was performed using commercial simulation software, and the SNP files of each distribution network simulation were cascaded to obtain the final 27-port amplitude and phase file for theoretical pattern calculation. The resulting pattern is nine petals.

[0032] 2. Analysis of simulation results

[0033] Reference Figure 6 , the directional pattern is nine petals, which means that the directional pattern has the ability of 135Hz envelope amplitude modulation.

[0034] In summary, the nine-petal pattern realization method proposed in the present invention has the characteristics of low loss, high integration, high reliability, high amplitude and phase consistency, etc. through a one-input three-output power distribution network, a three-input three-output amplitude and phase distribution network, and a cascade of digitally controlled phase shifters. Therefore, the present invention has certain application value in the field of high-precision navigation.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for realizing a nine-petal directional pattern, characterized in that: It includes a one-input three-output power distribution network, a three-input three-output amplitude-phase distribution network, and a digitally controlled phase shifter; wherein the one-input three-output power distribution network A1 has A1_1 as an input port, and A1_2, A1_3, and A1_4 as output ports; the three-input three-output amplitude-phase distribution network B1 has B1_1, B1_2, and B1_3 as input ports, which are connected to A1_2, A1_3, and A1_4 respectively, and B1_4, B1_5, and B1_6 as output ports. outlet; the digitally controlled phase shifter is between A1_2 and B1_1, A1_3 and B1_2; the one-input three-output power distribution network C1, C2, C3 are connected to B1, wherein C1_1, C2_1, C2_1 are connected to B1_4, B1_5, B1_6 respectively; the one-input three-output power distribution network D1 to D9 are connected to C1, C2, C3, wherein D1 is connected to C1_2, D4 is connected to C1_3, and D7 is connected to C1_4.

2. A method for realizing a nine-petal pattern according to claim 1, characterized in that: The one-input three-output power distribution network has 27 output ports D1 to D9, which are connected to 27 columns of uniform circular array antennas.

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