Abstract: A field effect transistor comprising: a non-doped diamond layer which has a hydrogen-terminated surface; first and second p+diamond layers which are formed on the non-doped diamond layer and sandwich a hydrogen-terminated region; a source electrode which is formed on the first p+diamond layer and is made of metal; a drain electrode which is formed on the second p+diamond layer and is made of metal; an insulating layer which is formed on the hydrogen-terminated region of the non-doped diamond layer; and a gate electrode which is formed on the insulating layer, a mutual conductance being equal to or higher than 0.5 mS/mm at room temperatures, after an X-ray is applied for an amount of 5 Mgy.

Abstract: A radar receiver having a clutter-elimination filter in the receiver's intermediate frequency stage. The filter is centered on the intermediate frequency f.sub.i and has a transfer function in which a band-pass characteristic is superimposed on a band-rejection characteristic. The band-pass response has a principal lobe substantially conforming to the function (sin x)/x with x=(w-w.sub.i).pi.T. The band-rejection response presents an attenuation zone centered about f.sub.i ; this zone is wide enough to suppress much of the response from clutter but narrow enough to avoid suppressing much of the energy in the echo from the target. For example, the width of the attenuation zone may be from about f.sub.i -0.2/T to about f.sub.i +0.2/T. The filter provides a maximum response on each side of the attenuation zone, spaced from f.sub.i by about 0.4/T Hz in each direction. Outside the maxima, the response is dominated by the band-pass characteristic and achieves transmission minima at about 1/T Hz above and below f.