Passive filter, also known as LC filter, is a filter circuit composed of a combination of inductance, capacitance and resistance, which can filter out one or more harmonics. The most common and easy to use passive filter structure is to connect the inductance and capacitance in series, which can form a low impedance bypass for the main harmonics (3, 5 and 7); Single tuned filter, double tuned filter and high pass filter are all passive filters.
The passive filter is composed of capacitor string reactance.
According to the harmonic condition of the system, for example, there are 5th harmonics, and the harmonic frequency is 250Hz.
At this time, the capacitance and reactance of the passive filter are matched, and they resonate at the frequency of 250Hz. Because the total impedance of the two resonates in series is 0, which is commonly known as the low impedance loop, at this time, all the 5th harmonic will flow into the passive filter to achieve the filtering effect.
Due to process reasons, generally speaking, the passive filter can achieve about 245-250Hz, and the filtering effect can reach more than 80%.
It has good frequency selection and filtering functions in circuits and electronic high-frequency systems, and can suppress useless signals and noise outside the frequency band.
It is used for aviation, aerospace, radar, communication, electronic countermeasure, radio and television and various electronic test equipment.
When using, pay attention to the good grounding of the shell, otherwise it will affect the out of band suppression and flatness index.
28-31GHz waveguide Harmonic Filter |
|
Signal Bandwidth |
28-31GHz(3000MHz BW) |
Center frequency |
29.5GHz |
Passband insertion loss |
≤0.25dB |
Passband insertion loss variation |
≤0.1dB |
VSWR |
≤1.2 |
Power |
≥200W |
Rejection |
≥60dB @56-62GHz和84~93GHz |
Material |
Copper |
Port Connectors |
APF28 |
Surface Finish |
Paint |
Temperature range |
-40℃~+70℃ |
28GHz -31GHz waveguide bandstop filters |
|
Signal Bandwidth |
28GHz -31GHz(3000MHz BW) |
Center frequency |
29.5GHz |
Passband insertion loss |
≤0.2dB |
Passband insertion loss variation |
≤0.1dB |
VSWR |
≤1.2 |
Power |
≥200W |
Rejection |
≥60dB @18GHz ~21.2GHz; 25GHz~27GHz |
Material |
Copper |
Port Connectors |
APF28 |
Surface Finish |
Paint |
Temperature range |
-40℃~+70℃ |