FilSynth is capable of synthesis and design almost all commonly used types of radio frequency and microwave passive filters including bandpass filters, bandstop filters, lowpass filters and highpass filters with essentially no limitation. The transmission zero can be placed freely within the attenuation bands. For bandpass type filter, N+2 type of coupling matrix is used so that source and load coupling can be synthesized. For bandstop type filter, transmission zeros can be placed anywhere within the stop band and yet filter parameters can be synthesized directly with only one external admittance.

Main filter characteristics and specifications are entered and summarized in one common Requirement Window. User can go back to requirement window and make the changes at any time during the use of the program. All sub-windows are updated together.