Inexpensive chip carriers for 10-port phase controlling MMIC's in the Ku band

A solution for relatively inexpensive chip carrier for multi-port phase controlling MMIC's in the Ku band is presented in this paper. The basic aim of the chip carrier design is the achieving of high enough isolation between the relatively close situated 8 input and 2 output ports. First, the input ports are placed perpendicularly to each other. Second, fully grounded coplanar waveguide arrangement of the chip carrier embedding paths is used. The both, upper and bottom grounded metallization of the carrier are properly connected with optimized array of via holes. The input embedding signal paths on the carrier are additionally matched to the impedance of the single wire bonds with given lengths. Different types of interconnections to the antenna printed circuit board are also investigated and a lateral metallization is chosen due to its better manufacture reproducibility. The S-parameters of the embedding path of chip carriers on TMM10i substrate are estimated with custom designed chip phantoms. The measurement gives the following data: insertion losses -0.45 dB, return losses -22 dB, isolation better than -27.5 dB at the frequency 12.5 GHz. These results are very close to these obtained by 3D Ansofi HFSS simulator. On this base the conclusion is that the utilization of the considered chip carrier ensure acceptable RF performances practically for all packaged MMIC's, which are able to satisfy the dc and digital functionality test. The obtained statistical deviations for the MMIC parameters in the frequency range 12.2-12.7 GHz are /spl plusmn/ 0.5-0.6 dB for the insertion gain, /spl plusmn/ 2-3 dB for the return losses and /spl plusmn/ 5-10/sup 0/ for the insertion phase shift. The corresponding tolerances, which are connected to the own chip carrier parameters, are smaller - /spl plusmn/ 0.25 dB for IL and /spl plusmn/ 1.0 dB for RL.