An RF High pass filter is a filter that blocks low frequencies and passes the higher frequencies. Every high pass filter (HPF) is designed around a ‘Cutoff’ frequency which is the frequency below which there will be high attenuation and above which there will be very low loss. So a HPF allows easy passage of the signals above cutoff frequency and mitigates the signals below the cutoff frequency.

The frequency response of a high pass filter can be understood through the terminology of Stopband and Passband. The stopband is the frequency up to the cutoff frequency and the passband is the frequency above the cutoff.

The high pass filter can be first order, second order, third order or so on according to the application requirement. The higher the order of the HPF the sharper the cutoff frequency transition.

Here is a list of some important parameters when searching for a RF high pass filter:

● Cutoff Frequency: The cutoff frequency of high pass filter is frequency at which the passband of the filter starts i.e below this frequency the filter will block all signals and above this the filter will pass all frequencies. There is an upper limit to the passband frequency in a high pass filter (if not specified in the datasheet, this is something you can ask the manufacturer).

● Bandwidth: The bandwidth (BW) of a high pass filter is the frequency range that an HPF can pass with minimal loss.

● Attenuation: This is the isolation or attenuation provided by the HPF below the cut-off frequency. It is expressed in dB.

● Insertion Loss: This is the loss the HPF provides in above the cut-off frequency.

● Power: This is the maximum input power that a filter can handle.

Kete has listed high pass filters in the links http://www.ketemicro.com/pro_info56.html. You can visit and choose filters.