Bandwidth and centre frequency of mask-tuned microwave plasma gratings in semiconductor coplanar waveguides

Tunable-filter operation of an optoelectronically generated periodic microw ave structure in a semiconductor-based CPW Can be achieved by means of a CW -illuminated slot array mask of linearly graded slot width, transversely mo ved across the waveguide surface. The photoexcited grating sections exhibit planes of plasma discontinuity which are obliquely positioned with regard to the transverse cross section of the CPW. From this, filter bandwidth and Centre frequency become sensitive to the various angles of obliquity. The corresponding relationship is analyzed and discussed in detail.