ECHO Microwave's substrate high pass filters reject low-frequency signals while passing all frequencies above the cutoff with minimal attenuation. The suspended substrate stripline architecture ensures consistent performance across wide bandwidths, with lower dielectric loss and better field confinement than standard microstrip high pass designs. These filters are used to define the lower frequency boundary of wideband receivers, block sub-harmonic mixing products, and isolate high-frequency signal paths in multi-band RF front-end systems. Thin Film versions provide a compact SMT-compatible alternative for applications from 6 GHz to 40 GHz where board space and production scalability are priorities. Our substrate high pass filters support frequencies from 1 GHz to 50 GHz and are available in connectorized packages with power handling up to 10W, serving military, aerospace, radar, and satellite communication platforms.