50 μ characteristic impedance low-pass metal powder filters

We have fabricated several 50 characteristic impedance low-pass metal powder filters. The filters are made with bronze or copper metal powder with varying amounts of metal powder in a metal powder/epoxy mixture. Our goal is to make a filter with a characteristic impedance Z=50 at frequencies up to 10 GHz. Using a 78% bronze powder/epoxy mixture in a suitable geometry, we achieved an impedance Z=54 at 4.2 K, with a cutoff frequency fc ≃0.3 GHz and an attenuation A= Vout Vin =0.0001 (-80 dB) at 10 GHz. We also made several non-50 low-pass bronze powder filters with fc =1 MHz and A=0.0001 at 10 MHz. Fabrication details and performance data will be presented for both types of filter. © 2007 American Institute of Physics.