title: Design and development of 3 dB patch compensated tandem hybrid coupler.
abstract: Design and development procedure of the strip line based 3 dB patch compensated tandem hybrid coupler at 91.2 ± 15 MHz and 2.5 kW is presented. The coupled strip-line structure is designed and electromagnetic analysis software is used for accurate modelling and optimization of parameters. Coupled strip lines are well known for poor impedance matching and poor isolation due to discontinuities, fabrication tolerance constraints, and theoretical approximations in design. These effects are realized and compensated or taken into consideration. The conventional methods of compensation like open stubs or lumped capacitors are useful in the low rf power applications only. In the present paper, patch compensation technique is explored, explained, applied, and incorporated in the development of a 3 dB tandem hybrid coupler. This newly explored patch compensation technique is found substantially effective in improving the overall performance in terms of return loss and isolation. A prototype tandem coupler rated for 2.5 kW at 91.2 ± 15 MHz, has been developed, fabricated, tested, and the effect of patch compensation technique is found to be quite effective.
authors: Institute for Plasma Research, Bhat, Gandhinagar 382 428, India. rpyadav@ipr.res.in
authors: Rana Pratap
authors: RP
authors: Yadav
authors: Sunil
authors: S
authors: Kumar
authors: S V
authors: SV
authors: Kulkarani