| In this thesis several passive and active MMIC structures are designed, fabricated and tested in order to develop a monolithic transmit/receive system residing on a single chip with enhanced performance at millimeter-wave frequencies. The capability of applying micromachining to improve the efficiency of microstrip patch antennas on high index materials such as silicon, GaAs, or InP is validated. Patch antennas on Duroid substrates resonating at 13 GHz with 64% and 28% increase in impedance bandwidth and efficiency, respectively, as well as smooth radiation patterns are successfully demonstrated by creating a cavity underneath the antenna. The importance of the placement of the cavity relative to the radiating edges of the antenna in order to improve the efficiency is also shown. A minimum distance equal to two times the substrate thickness is required. A planar micromachined resonator on silicon with a high quality factor, Q, at 10.4 GHz is also fabricated and tested; the measured Q is 506 while the insertion loss and the bandwidth are 0.36 dB and 5%, respectively. A bandwidth of 2% with a loss of 1.1 dB is also achieved for a slightly different topology of the micromachined resonator. Insertion loss measurements under different temperature ambients showed a negligible drift in the resonant frequency.; Regarding active structures, Finite Ground Coplanar line based monolithic multipliers and mixers operating in W-band are designed, fabricated and tested. The performance of FGC lines on GaAs and quartz substrate with a polyimide overlay for passivation is first investigated. Experimental results that show the dependence of the line characteristics on the geometry rather than the substrate material are presented. Next, a Q = 2 monolithic doubler with 17.2% efficiency, 10% minimum bandwidth and 66 mW output power, as well as a Q = 3 doubler with 22% efficiency, 8.5% bandwidth and 50 mW output power in W-band are demonstrated. A doubler from 37.5 to 75 GHz that implements four diodes with a 12.5% efficiency and an output power of 115 mW is also presented. Furthemore, a method that increases the efficiency of monolithic multipliers by reducing the loss of the FGC lines is shown. Finally, a monolithic mixer residing on the same material with the multipliers is fabricated and tested. A novel fabrication technique that combines channel etched diodes of small areas with air-bridges for the passive circuits is developed. A single-sideband conversion loss of 11 dB is achieved at 79 GHz for an IF frequency of 4 GHz and an LO power of 8.8 dBm. |
