This standard applies to the measurement of power capacity. SJ 2534.16-1987 Antenna test method Power capacity measurement SJ2534.16-1987 Standard download decompression password: www.bzxz.net
This standard applies to the measurement of power capacity.

Standard of the Ministry of Electronics Industry of the People's Republic of China Antenna Test Method
Measurement of Power Capacity
This standard applies to the measurement of power capacity. 1 Factors limiting power capacitywwW.bzxz.Net
SJ2534.16-87
The power capacity of an antenna refers to the ability of the antenna to withstand power. The power capacity is limited by the heating of the metal or dielectric at high average power levels, and by arc discharge, voltage breakdown or corona discharge associated with strong electric fields at high peak power levels.
2 Relationship between breakdown and physical properties of the air around the antenna 2.1 Relationship between breakdown and air pressure
The breakdown is related to air pressure. When the air pressure is very low, the breakdown power level decreases with increasing air pressure. The air pressure at which it reaches the minimum value (glow discharge) is related to the wavelength. At high air pressure, it increases with increasing air pressure. When measuring power capacity under high vacuum conditions (such as at satellite altitude), secondary electron multiplication is a possible breakdown mechanism for any antenna. Secondary electron multiplication is an antenna resonance phenomenon that occurs under high vacuum conditions. When the electron transit time from one electrode to the other of the antenna is comparable to the inverse of the operating frequency, the surface ionization caused by electron collisions leads to an increase in the electron density.
2.2 Breakdown Phenomenon in Plasma Environment
For antennas mounted on re-entry vehicles, the power capacity should be determined when the vehicle is surrounded by ionized air. When the antenna's transmission power is increased to a certain level, the power absorbed by the ionized gas is sufficient to heat the gas and increase the electron density. In this case, the most important parameter for determining breakdown is the critical plasma density. The definition of breakdown is related to the size of the initial plasma density.
2.2.1 Critical Plasma Density
The plasma density when the natural oscillation frequency of the ionized gas is equal to the antenna excitation frequency is called the critical plasma density. When the natural oscillation frequency of the ionized gas is much lower than the antenna excitation frequency, the plasma is called below the critical density or low density.
2.2.2 Definition of breakdown when the initial plasma density is below the critical density If the initial plasma density is well below the critical density, the effect of the undisturbed gas on the antenna field can be ignored. In this case, breakdown is defined as the input power that causes the disturbed ionized gas to become supercritical (overdense) and causes a sharp drop in the transmitted power outside the plasma.
2.2.3 Definition of breakdown when the initial plasma density is close to the critical density If the initial plasma density is close to or exceeds the critical density, the definition of breakdown is more complicated, and the undisturbed ionized gas may have a serious effect on the antenna field and usually cannot be ignored. In this case, the general definition of breakdown refers to a specific input power level, when the input power exceeds this level, the transmitted power outside the plasma no longer increases significantly. 3 Measurement of power capacity
Promulgated by the Ministry of Electronics Industry on January 6, 1987
Implemented on June 1, 1987
SJ2534.16-87
Because antenna structures and environmental conditions vary, this standard does not specify specific test procedures for power capacity, but only mentions general issues of measurement.
3.1 Simulation of environmental conditions
When the altitude is high, the antenna operates under low pressure conditions. At this time, in order to satisfactorily measure the peak power capacity, a bell jar or other suitable small chamber must be used to simulate the altitude conditions. Note: Extrapolation from the measured data at sea level is unreliable. The method of using radioactive materials to continuously form free electrons in the air around the antenna under test can be used to ensure the reliability and consistency of the breakdown test without reducing the absolute breakdown threshold. When measuring the power capacity of missile antennas in the laboratory, plasma conditions must be simulated. The breakdown power level may be critically related to several plasma parameters and to the magnitude and spatial variation of the electron density. When testing an antenna, not only the breakdown power level should be measured, but also the input impedance, radiation pattern, change in power gain, and distortion of the transmitted signal should be measured at power levels below, equal to, and above the breakdown level. 3.2 Transmitter Parameters
For accurate results, the parameters of the power source used for the measurement (e.g., modulation, pulse shape, pulse width, and pulse repetition frequency) should be the same as those of the transmitter actually used for the antenna. 3.3 Impurities
During testing, the antenna should be carefully inspected for burrs, dirt, metal debris, and rust, which are often the main factors that reduce the breakdown power.
3.4 ​​Monitoring
The temperature rise can be measured using thermocouples or temperature-sensitive coatings applied to critical surfaces. Depending on the type of test monitor used, breakdown can be detected by external observation, listening, changes in the signal received by the transmission monitor antenna, or changes in the reflected wave monitor signal as the applied power level increases. Sometimes (e.g. in the case of glow discharge) the critical issue is to determine the power level at which breakdown stops once it has occurred. 3.5 Safety precautions
When making measurements at high average power levels, appropriate safety devices and methods should be used to protect nearby personnel from injury.
Additional remarks
This standard was proposed by the Standardization Institute of the Ministry of Electronics Industry. This standard was drafted by the 39th Institute of the Ministry of Electronics Industry. The main drafter of this standard: Ke Shuren
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