This standard applies to the measurement of the radiation pattern of the antenna in the antenna test field, with emphasis on the measurement of the antenna radial pattern. This standard always assumes that the test antenna is a passive, linear, and reversible device, so its radiation conversion can be measured in both the transmitting state and the receiving state. Otherwise, the measurement should be carried out in the designed use state of the antenna system. If there is no special description in this standard, the test antenna is used in the receiving state. SJ 2534.3-1984 Antenna test method Measurement of antenna radiation pattern in the antenna test field SJ2534.3-1984 standard download decompression password: www.bzxz.net
This standard applies to the measurement of the radiation pattern of the antenna in the antenna test field, with emphasis on the measurement of the antenna radial pattern. This standard always assumes that the test antenna is a passive, linear, and reversible device, so its radiation conversion can be measured in both the transmitting state and the receiving state. Otherwise, the measurement should be carried out in the designed use state of the antenna system. If there is no special description in this standard, the test antenna is used in the receiving state.

Standard of the Ministry of Electronic Industry of the People's Republic of China SJ2534.3-84
Antenna Test Method
Measurement of Antenna Radiation Pattern in Antenna Test Field Published on November 1, 1984
Implementation on July 1, 1985
Approved by the Ministry of Electronic Industry of the People's Republic of China.
Standard of the Ministry of Electronic Industry of the People's Republic of China Antenna Test Method
SJ2634.3-84
Measurement of Antenna Radiation Pattern in Antenna Test Field This standard is applicable to the measurement of antenna radiation pattern in antenna test field, with emphasis on the measurement of antenna radiation pattern. The antenna under test is always defined as a passive, linear, reversible device, so its radiation characteristics can be measured in both the transmitting state and the receiving state. Otherwise, the measurement should be carried out in the designed use state of the antenna system. Unless otherwise specified in this standard, the antenna under test is used in the receiving state. Basic considerations for working coordinate system and measurement
1.1 Antenna radiation pattern is the main characteristic of any antenna. In order to fully characterize the radiation field of an antenna, the relative amplitude, relative phase, polarization and power gain on a sphere centered on the test antenna (strictly speaking, centered on the phase center of the test antenna) should be measured. Any of these radiation characteristics displayed as a function of the spatial coordinates is defined as the radiation pattern or antenna pattern of the test antenna. 1.2 A working coordinate system (usually a spherical coordinate system) should be associated with the test antenna. This coordinate system is determined by the system in which the antenna is used. Different coordinate systems can be specified for the measurement of special antennas. The standard spherical coordinate system used in antenna measurement is shown in Figure 1: A coordinate system specifically used for rockets, missiles and spacecraft is shown in Figure 2. 1.3 The coordinate system of the antenna is generally specified based on a mechanical reference on the antenna. Therefore, a means of establishing this mechanical reference should be provided.
The Ministry of Electronics Industry of the People's Republic of China Issued on November 1, 1984 Implemented on July 1, 1985
中=270
Antenna-containing
Meter
SJ2534.3-84
Antenna position
9=160*
中=96
Figure 1 Standard ball mark system used in antenna test dish
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Figure 2 A special base mark system
SJ2534.3-84
1.4 In a given radiation pattern, two angular coordinates are variables, while the distance R from the test antenna to the measurement point is constant. Usually the RF operating frequency and the antenna polarization state are treated as parameter variables. The radiation pattern should be measured at the specified frequency and in the specified polarization state. For some antenna applications, the frequency must be used as a variable. If the frequency is continuously variable, this measurement method is called a swept frequency technique.
1.5 It is not practical to fully measure the radiation pattern of the antenna, so various sampling techniques must be used. For example, the operating frequency and polarization are fixed and the coordinates are changed step by step. For each increment of ?, the required antenna characteristics are continuously measured within a given Φ range. According to the actual situation, as long as the increment is small enough, a nearly complete practical antenna pattern can be obtained. The pattern obtained for all 0 increments is usually called a radiation pattern group. 1.6 When the source antenna irradiates the components in its immediate vicinity, these components will change the radiation field of the isolated antenna, so the measurement of the radiation field must include the relevant parts of those components. Scaled models are commonly used in these occasions. For the above reasons, the term "test antenna" (sometimes referred to as the antenna to be tested or the antenna under test in the information) in this standard refers to the antenna itself plus any components with the antenna. This means that the volume of the test antenna is generally larger than the volume of the antenna itself.
2 Cutting of antenna pattern
2.1 The direct method of measuring the antenna auxiliary radiation pattern is to use an appropriate source antenna, which is installed so that it can move along a curve with 0 as a constant and Φ as a constant relative to the test antenna (see Figure 1). The direction trajectory with Φ as a constant is a cone. Therefore, the measurement made when Φ is a variable and Φ is a parameter variable is called a cone cut or Φ cut. The measurement made when Φ is a variable and ? is a parameter variable is called a great circle cut or 0 cut. The cone cut of =90 is also a great circle cut. 2.2 When the direction trajectory is required to make a spiral motion, 0 and Φ are both variables, and the resulting motion is called a spiral cut. Usually the motion in the 0 direction changes much more slowly than the motion in the 9 direction. Therefore, the radiation pattern obtained by rotating 360° in the Φ direction is approximately a cone cut. 2.3 The orthogonal great circle cut through the main lobe axis of the test antenna is called the main plane cut. According to this definition, the beam axis should be located in the equatorial plane of the standard spherical coordinate system (0=90°) or at a pole (0=0° or 0=180°). 2.4 If the positioner system is designed for 0 and 9 cuts, then avoid aligning the beam axis of the pencil beam antenna with the pole. This is because for the direction of 0=0°, the Φ cut will only obtain the polarization pattern of the test antenna. When approaching the pole, for the Φ cut, unless the incident field is a constant circular polarization, the polarization direction of the incident field changes drastically relative to the polarization of the test antenna. Therefore, for the pencil beam antenna, the passband should set the antenna beam axis in any desired direction in the equatorial plane (mostly in the direction of 9=0° or 9=180°). 3 Basic configuration forms of antenna test field
3.1 It should be pointed out that the antenna radiation pattern described in this standard refers to the far-field pattern of the antenna. There are two basic test field configuration forms that can achieve the positioning requirements of the Φ cut: fixed line of sight form and movable line of sight form.
3.2 Fixed sightline form: In this form, the antenna under test and its associated coordinate system rotate around an appropriate axis (usually the axis passing through the phase center of the antenna under test). The source antenna is placed at a suitable position at a distance (in 3
SJ2534.3-84
"Design of Antenna Test Field" (SJ2534.2-85), the distance between the two antennas is R>2(D: +D,) 2).
If the antenna under test is working in the receiving state, the signal received from the source antenna is recorded. The fixed sightline form is generally used. As long as the antenna under test uses a positioner that can be cut with 9 in actual application, it is very convenient to use this form to measure the test line. 3.3 Movable sightline form, in this form, the source antenna moves step by step or continuously along a circle with its center approximately located at the phase center of the antenna under test. If the source antenna moves step by step, for each position of it, the antenna under test is rotated and the received signal is recorded. On the contrary, the antenna under test rotates in steps, and the source antenna moves continuously along its circular orbit for each position. The movable line of sight form is suitable for the following measurement situations: small antennas, model antennas or primary feed sources of antennas, large fixed ground antennas or antenna structures that are large and bulky and inconvenient to rotate or have special requirements for measurement (such as in the measurement of large electrical antennas), when the antenna installation site and environment are the main parts of the radiation system and cannot be ignored (such as in "field measurement of antenna radiation pattern"): sometimes it is also used for the identification of overall antenna engineering. 4 Representation of antenna amplitude radiation pattern
4.1 Antenna amplitude radiation pattern can be recorded in polar coordinates or rectangular coordinates according to different situations. It can also be represented by equi-level line diagrams and radiation distribution. 4.2 Polar coordinate radiation pattern: It is more intuitive, and it is easy to see how the radiation is distributed in different directions in space. But it is not very suitable for the representation of narrow beam radiation patterns. 20
208180-170150
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Relative field strength diagram
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19017010
SJ2534.3-84
F9)/max
bRelative power diagramwww.bzxz.net
cDecibel diagram
Figure 3 Different representations of the amplitude radiation pattern of the same antenna8
4.3 Rectangular coordinate radiation pattern: It is more flexible because it can appropriately widen the narrow beam by changing the transmission speed ratio between the recording paper tape servo system and the antenna positioner, thereby fully expressing the details of the narrow beam such as the main lobe width, secondary lobe and zero value position. 4.4 The most commonly used amplitude scales for amplitude patterns are relative field strength, relative power (usually the maximum value is set to 1) and the logarithm of relative gain (usually the maximum value is set to odB). 4.4.1 The relative field strength pattern shows the change in electric field strength as a function of angular coordinates at a certain distance from the antenna (see Figure 3a). The sidelobe resolution of the field strength pattern is high, and the field strength cannot clearly show small level changes near the maximum value. The half-power level of this form is 0.707 of the maximum value. 5
SJ2534.3-84
4.4.2 The relative power pattern shows the variation of the power density as a function of the angular coordinate at a certain distance from the antenna (see Fig. 3b). The power pattern is most useful when it is necessary to determine small power changes between 100% and 10% of the maximum power. In the range below 10% of the maximum power, it is difficult to distinguish the power changes without changing the gain level. The power pattern is used in the calculation of directivity. It is sometimes used to determine the half-power beamwidth of the antenna main lobe because the resolution of the power pattern is high at higher levels. Obviously, the power pattern is not suitable for measurement situations with very low sidelobe levels and high front-to-back ratios. 4.4.3 The logarithmic pattern of relative gain is the most commonly used. This pattern can be obtained if the amplitude coordinate of the amplitude pattern is linearly scaled in decibels. This form is particularly useful because antenna gain is usually expressed in decibels. The decibel scale has a constant resolution over the entire display range. The decibel scale has a wider display range than other forms. This is very useful for studying low sidelobes and null depths. The decibel scale also makes it easier to compare patterns, because the difference in system gain is equivalent to a constant difference in the recorded data. A 40dB measurement range is generally required for measurements, which is sufficient to represent the sidelobe level of interest and has sufficient resolution to study the mainlobe structure (see Figure 3C). However, when working with a square law detector, in order to obtain a 40dB dynamic range, the recorder should have an available dynamic range of 80dB. In order to make the recorder noise level less than the minimum input signal level, the noise level is generally required to be 110 to 120dB lower than the full-scale input. In special measurements, such as the measurement of high-quality satellite communication ground station antennas, a 60dB or even wider dynamic range may be required. At that time, a precision test receiving device with high receiving sensitivity and wide dynamic range should be selected. 4.5 The equal-level line diagram is to connect the equal-signal level points with lines on a two-dimensional plane of 9 to form equal-level lines. In this way, the complete antenna amplitude pattern can be represented on a piece of paper with equal-level lines. Different important levels on the diagram are indicated by numbers, or by different colors. The advantage of the contour line diagram is that the data of the main lobes in three-dimensional space can be represented on a two-dimensional coordinate. This method requires the use of computer graphics. The contour line diagram can be drawn in rectangular coordinates, polar coordinates or other specific coordinates as required. 4.6 The radiation distribution table can provide the same basic information as the contour line diagram, but the implementation method is simpler, that is, the decibel number of the signal level is printed on the pre-selected intervals of 0 and 9. Figure 4 shows a part of a radiation distribution table. The specific method is: scan in the 9 direction, and step an increment in the direction after each 9 cut. The angular increments in the 9 and Φ directions in the figure are both 0.5, and the dynamic range is 40dB. The signal level is detected by an encoder connected to the servo-driven logarithmic potentiometer in the antenna pattern recorder and printed on the data table with an improved typewriter. If only the even value of the signal level is printed and the odd value is omitted, or a horizontal line is added under the even value or odd value, the effect of the contour line is obtained. In areas where the pattern changes slowly, the accuracy of equal levels can be improved by interpolation. By program-controlled positioner stepping values ​​one by one and performing Φ cutting, the radiation distribution table can be quickly obtained and sufficient data can be provided on one graph to measure the total radiation of the antenna pattern. Its disadvantages are that the value changes are discontinuous, the zero value depth and zero zone details cannot be recorded, and it is not as intuitive as a two-dimensional pattern. 0
SJ2534.3-84
Part of the radiation distribution table
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