Suspended substrate filter technology uses air cavity construction achieve high Q and avoid the adverse effects of dielectric materials used in traditional stripline construction. The resulting performance gives designers the advantages of wide passbands with low insertion loss and stopband rejection on the order of 100 dB with fast roll-off. This paper reviews the fundamentals of suspended substrate filters, key performance features and the unique manufacturing challenges associated with these useful building blocks for wideband systems.

Suspended substrate filter technology uses air cavity construction achieve high Q and avoid the adverse effects of dielectric materials used in traditional stripline construction. The resulting performance gives designers the advantages of wide passbands with low insertion loss and stopband rejection on the order of 100 dB with fast roll-off. This paper reviews the fundamentals of suspended substrate filters, key performance features and the unique manufacturing challenges associated with these useful building blocks for wideband systems.

Ultra-Wideband (UWB) radio is defined as any RF technology utilizing a bandwidth of greater than ¼ the center frequency or a bandwidth greater than 500 MHz [1] [2]. While UWB has been a known technology since the end of the 19th century, restrictions on transmission to prevent interference with narrow-band, continuous wave signals have limited its applications to defense and relatively few specially licensed operators [1].

Ultra-Wideband (UWB) radio is defined as any RF technology utilizing a bandwidth of greater than ¼ the center frequency or a bandwidth greater than 500 MHz [1] [2]. While UWB has been a known technology since the end of the 19th century, restrictions on transmission to prevent interference with narrow-band, continuous wave signals have limited its applications to defense and relatively few specially licensed operators [1].

“High-performance, millimeter-wave MMIC products” and “cost-effective surface mount lead-frame-based packaging” typically don’t come up in the same conversation, and for good reason. Just two or three years ago, it was difficult to conceive of operating at frequencies above 20 GHz without considering an expensive, open cavity, HTCC package or resorting to more bespoke chip and wire assemblies.

Since the advent of Network Synthesis Theory at the turn of the last century, filter designers have been developing ever more sophisticated solutions to translate polynomial transfer functions into working, physical components.