A 135 Ghz Cmos Marchand Balun With Ground Sheilds

Nowadays, the realization of ultra-high-speed wireless communications using millimeter-wave bands is expected. A new type of balun, which is small in size, wide in bandwidth and low in loss, is needed. However, conventional baluns have a problem that the SI substrate is bare and the loss increases at high frequencies. In this study, we propose a lowloss marchand balun with a ground metal shield on the coupled lines, such as a grounded coplanar waveguide. The results of the measurements, a new marchand balun was successfully developed with the lowest insertion loss in the millimeter-wave balun, i.e., a center frequency of 133 GHz, a bandwidth of 46 GHz, and a loss of less than 2 dB, which has excellent performance in amplitude imbalance and phase imbalance, although it is simulated.