ANALYSIS OF LOW-PASS FILTERS CONSISTING OF MULTIPLE STACKED FSSS OF DIFFERENT PERIODICITIES WITH APPLICATIONS IN THE SUBMILLIMETER RADIOASTRONOMY

A spectral domain approach is presented which allows multiple stacked frequency selective screens (FSS's) to be investigated. The analysis i s exact if all arrays have the same periodicity or if a unit cell of f inite extent valid for the whole FSS can be defined. Further, this app roach can be used as a very efficient approximation for analyzing low- pass filters applied in the radioastronomy and consisting of arrays wi th different periodicities, as long as the unit cell dimensions and th e separation between the arrays are small compared to a wavelength at the operating frequency. Numerical results for several FSS configurati ons are presented and compared with measured values.