High frequency partial discharge test GTEM chamber

NegotiableUpdate on 05/18

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Nature of the Manufacturer: Producers

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Overview

The characteristic impedance inside the high-frequency partial discharge test GTEM chamber is still designed to be 50 Ω. In order to reduce the reflection of input electromagnetic waves at the end of the internal cavity, the end of the core board is connected to a broadband matching load board, and an absorbing material is also placed at the end of the cavity to absorb the electromagnetic waves emitted to the end.

Product Details

GTEM is a single port enclosed waveguide with a frequency of up to 20GHz. As a testing environment for radiation emission and radiation immunity testing in the industry, in addition to the commonly used anechoic chamber, the International Electrotechnical Commission (IEC) also specifies a TEM based testing method. The characteristic impedance inside the GTEM chamber is still designed to be 50 Ω. In order to reduce the reflection of input electromagnetic waves at the end of the internal cavity, the end of the core board is connected to a broadband matching load board, and an absorbing material is also placed at the end of the cavity to absorb the electromagnetic waves emitted to the end.

The structural composition of GTEM chamber:

1. Signal source: It is a signal source with GPIB interface. It can also perform offline or online operations. When online, it can be controlled by a computer to perform corresponding operations.

2. Power amplifier: amplifies the small signal of the signal source and sends it to the small room to form the required field strength.

3. Field strength probe: measures the electric field strength inside the small room and sends the level value of the field strength signal to the field strength monitoring instrument through a cable for processing.

4. Field strength monitor: processes signals from field strength probes and displays the field strength value at the location of the indoor probe on the screen. The field strength monitoring device can be operated independently of the computer (through the buttons on the panel, see the instructions for use); It can also be connected to a computer through GPIB (IEEE-488) interface.

5. Main control computer: equipped with a standard GPIP interface card, connected to the field strength meter through a cable. By using a main control computer and configuring necessary system software, synchronous control of the field strength monitoring instrument and signal source can be achieved, realizing the automation operation of the entire testing system.

The GTEM chamber is made of absorbing materials to create a closed space, which can create a pure electromagnetic environment in the darkroom. The microwave anechoic chamber material can be any absorbing material, with the main material being polyurethane absorbing sponge SA (used at high frequencies). In addition, when testing the electromagnetic compatibility of electronic products, ferrite absorbing materials are also used due to low frequencies. Its main working principle is based on the law of electromagnetic waves propagating from low magnetism to high permeability in a medium, using high permeability absorbing materials to guide electromagnetic waves. Through resonance, a large amount of electromagnetic radiation energy is absorbed, and then the energy of electromagnetic waves is converted into thermal energy through coupling.

The recommended key component indicators for the UHF ultra-high frequency partial discharge detection GTEM measurement platform are as follows:

1. GTEM Chamber:

Frequency range: DC~2GHz;

Input impedance: Typical value: 50 Ω± 2 Ω;

Voltage standing wave ratio: ≤ 1.5;

Specification and dimensions: not less than 4000 × 2100 × 1400mm (length × width × height);

The sensor testing window on GTEM is located in the top third of the area with relatively uniform field strength, with an opening diameter of ≥ 150mm.

2. Calibration source:

Output square wave or double exponential pulse with adjustable amplitude from 0 to 100V;

Rising edge (20%~80%) ≤ 300ps;

Half wave time of 4ns to 100ns;

The repetition rate should be between 50-200Hz.

3. Reference sensor

Short monopole probes have the characteristic of undistorted reception, and it is recommended to use monopole probes as reference sensors.

4. Oscilloscope

The analog bandwidth requirement of the oscilloscope is not less than 2GHz, and the sampling rate is not less than 10GS/s