Method for measuring reflection coefficient of radome by using transmission type radome test system

Abstract

The invention relates to the field of microwave testing, in particular to a method for measuring the reflection coefficient of an antenna housing through a transmission testing system. Comprising the following steps: setting a test polarization mode; adjusting the antenna housing mounting rack according to the test part and the incident angle of the to-be-tested antenna housing; before the to-be-tested radome is installed, recording the transmission amplitude and phase of the free space when the radome does not exist, and taking the transmission amplitude and phase as test reference values; and the transmission amplitude and the phase under the condition that the antenna housing exists are tested and are compared with the tested reference value to obtain the power transmission coefficient test amplitude and the phase delay of the antenna housing to the electric field, and then the reflection coefficient of the electric field of the antenna housing is obtained through formula calculation. The method is suitable for process detection quality control of manufacturers, the test principle is easy to understand, the test method is visual, and the method is more suitable for exploration and improvement of the performance of a prototype radome with high performance requirements and short development and production time.

Description

Technical Field

[0001] The invention relates to the field of microwave testing, and in particular to a method for measuring a reflection coefficient of a radome by utilizing a transmission testing system. Background Art

[0002] The power reflection test of the radome is an issue that needs to be paid attention to and controlled in the engineering design of the radome, especially the power reflection test of the airborne fire control and early warning airborne radar radome is more important, because this parameter directly affects the reflection lobe index. Although the arch method can test the power reflection of the flat plate (as shown in Figure 1), it is powerless for the power reflection test of the curved radome. The reflection type electrical thickness test system (as shown in Figure 2) can only test the insertion phase shift of the normal angle of the curved radome. The transmission type electrical thickness test system can more accurately test the insertion phase shift of the curved radome, but the existing transmission type electrical thickness test system is helpless for the power reflection test of the radome (as shown in Figure 3). So far, there is no method that can test the complex reflection coefficient of the curved radome under oblique incidence. Summary of the invention

[0003] The present invention proposes a method for measuring the reflection coefficient of a radome using a transmission test system. The method is applicable to radomes with a single-layer solid core structure. This patent solves the problem of measuring the power reflection of radome products with a single-layer solid core structure in theory and practice.

[0004] This invention provides a new technical route and powerful technical means for improving the design of curved airborne radomes, conducting full-process product quality monitoring and adjustment, and improving product performance systems in the future.

[0005] The present invention provides a method for measuring a radome reflection coefficient by using a transmission radome test system, wherein the transmission radome test system comprises a transceiver horn and a radome mounting frame, and comprises the following steps:

[0006] S1: Set the test polarization mode by adjusting the transceiver speakers;

[0007] S2: adjusting the radome mounting frame according to the test position and incident angle of the radome to be tested;

[0008] S3: Before installing the radome to be tested, record the transmission amplitude and phase of free space without the radome as the reference value of the test;

[0009] S4: Installing the radome to be tested on the radome mounting frame;

[0010] S5: Test the transmission amplitude and phase with the antenna cover, and compare with the test reference value to obtain the power transmission coefficient test amplitude and the phase delay φ of the antenna cover to the electric field; the power transmission coefficient test amplitude is numerically equal to ;

[0011] Where T is the complex transmission coefficient of the radome to the electric field;

[0012] φ is the phase delay of the radome to the electric field;

[0013] S6: According to formula (1), the reflection coefficient R of the electric field of the radome is derived;

[0014] (1)

[0015] Where R is the reflection coefficient of the electric field of the radome;

[0016] is the normalized characteristic impedance of the solid core layer of the radome to free space;

[0017] ;

[0018]

[0019]

[0020] in, , Δ are intermediate parameters.

[0021] Preferably, the method of adjusting the transceiver horn is to rotate the polarization axis of the transceiver horn.

[0022] Preferably, the antenna cover mounting frame is adjusted by adjusting the roll axis, the azimuth axis and the pitch axis.

[0023] Beneficial effects: The invention is suitable for the process detection quality control of manufacturers, the test principle is easy to understand, the test method is intuitive, and it is more suitable for the performance investigation and improvement of the initial sample antenna cover with high performance requirements and short development and production time. It provides strong support for the comprehensive quality management of the manufacturer's wartime mass production process detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The block diagram of the power reflection system for testing the radome flat panel for the arch method;

[0025] Figure 2 The block diagram of the reflective radome test system is shown below;

[0026] Figure 3 Block diagram of the transmission radome test system DETAILED DESCRIPTION

[0027] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A method for measuring a radome reflection coefficient using a transmission radome test system, wherein the transmission radome test system includes a transceiver horn and a radome mounting frame, and includes the following steps:

[0029] S1: Rotate the polarization axis of the transceiver speaker and set the test polarization mode;

[0030] S2: according to the test position of the radome to be tested, the radome mounting bracket is rotated to the corresponding position using the roll axis;

[0031] S3: adjusting the azimuth axis and the elevation axis of the radome mounting frame according to the incident angle required to be tested for the radome to be tested;

[0032] S4: Before installing the radome to be tested, record the transmission amplitude and phase of free space without the radome as the reference value of the test;

[0033] S5: Installing the radome to be tested on the radome mounting frame;

[0034] S6: Test the transmission amplitude and phase with the antenna cover, and compare with the test reference value to obtain the power transmission coefficient test amplitude and the phase delay φ of the antenna cover to the electric field; the power transmission coefficient test amplitude is numerically equal to ;

[0035] Where T is the complex transmission coefficient of the radome to the electric field;

[0036] φ is the phase delay of the radome to the electric field;

[0037] S7: According to formula (1), the reflection coefficient R of the electric field of the radome is derived;

[0038] (1)

[0039] Where R is the reflection coefficient of the electric field of the radome;

[0040] is the normalized characteristic impedance of the solid core layer of the radome to free space;

[0041] ;

[0042]

[0043]

[0044] in, , Δ are intermediate parameters.

[0045] The derivation process of formula (1) is described as follows:

[0046] The analytical formulas for the power transmission and reflection coefficient of the local plane of the solid core radome are:

[0047] (2)

[0048] (3)

[0049] Where: It is divided into two cases, horizontal polarization and vertical polarization, and calculated separately:

[0050] (4)

[0051] (5)

[0052] Subscript indicates parallel polarization, the subscript represents vertical polarization, is the relative complex permittivity of the radome core layer, is the incident angle, let:

[0053] , , ,

[0054] Where: is the thickness of the radome, is the transmission constant. These two values ​​are eliminated after derivation. They are intermediate variables and do not affect the calculation results if they are unknown.

[0055] Substituting into (2), we get:

[0056]

[0057] Arrange the equation:

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] From (2) and (3) we get:

[0064]

[0065] Remove the pseudo roots and set =1, in free space, , and the modulus of x should be 1, and should have a positive sign

[0066]

[0067] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for measuring a radome reflection coefficient using a transmission radome test system, wherein the transmission radome test system comprises a transceiver horn and a radome mounting frame, wherein: The following steps are involved: S1: Set the test polarization mode by adjusting the transceiver speakers; S2: adjusting the radome mounting frame according to the test position and incident angle of the radome to be tested; S3: Before installing the radome to be tested, record the transmission amplitude and phase of the free space without the radome as the reference value of the test; S4: Installing the radome to be tested on the radome mounting frame; S5: Test the transmission amplitude and phase with the antenna cover, and compare with the test reference value to obtain the power transmission coefficient test amplitude and the phase delay φ of the antenna cover to the electric field; the power transmission coefficient test amplitude is numerically equal to ; Where T is the complex transmission coefficient of the radome to the electric field; φ is the phase delay of the radome to the electric field; S6: According to formula (1), the reflection coefficient R of the electric field of the radome is derived; （1） Where R is the reflection coefficient of the electric field of the radome; is the normalized characteristic impedance of the radome solid core layer to free space; ； in, , Δ are intermediate parameters.

2. The method for measuring the reflection coefficient of a radome using a transmission radome test system according to claim 1, characterized in that: The method of adjusting the transceiver horn is to rotate the polarization axis of the transceiver horn.

3. The method for measuring the reflection coefficient of a radome using a transmission radome test system according to claim 1, characterized in that: The way to adjust the radome mounting bracket is to adjust the roll axis, azimuth axis and pitch axis.

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