58 GHz front ends for a channel sounder

We report on the design of radio frequency (RF) front ends for radio channel sounding applications at 58 GHz. The realized up- and down-converter modules extend the frequency range of an existing real-time channel sounder, which has a maximum RF of 5.8 GHz. To facilitate rapid mm-wave system development, a low-cost 60 GHz prototyping system is introduced. It allows one to test each circuit block in a microstrip test fixture, before connecting it to other circuit blocks using removable electrical and mechanical bonds. The design of V-band microstrip RF filters was challenging because the transverse dimensions of the coupled sections are too wide for utilizing TEM transmission line models and surface-wave effects introduce additional coupling. Electromagnetic optimization was necessary for successful filter design, and this is discussed. The patch antenna and considerations about system dynamic range requirements for multipath measurements are examined.