A survey of planar integrated mm-wave components

Different approaches for the integration of mm-wave components have been presented recently, suggesting image line or shielded microstrip line for example. A very promising attempt employs quasi-planar structures, like fin-line, and related line configurations for this purpose. The paper gives a survey of various components being developed in the frequency range from 18 to 170 GHz using this approach. Broadband p-i-n-attenuators achieve an insertion loss below 1 dB and an isolation better than 25 dB covering either one or two entire waveguide bands. Narrowband resonator-type attenuators need only one diode to achieve similar results. At 94 GHz the attenuation of such a device can be adjusted between 1.5 and 35 dB. Fin-line detectors have been built between 18 and 170 GHz, with minimum sensitivity ranges from 400 to 100 mV/mW, depending on frequency. The conversion loss of a planar balanced mixer developed for Ka-band (26.5¿40 GHz) amounts to 5 dB in a narrowband version and to 6¿8 dB in a broadband, octave-wide version (18¿40 GHz). For 60 GHz, a conversion loss down to 6.5 dB has been achieved. The unique advantage of the fin-line technique is demonstrated by a completely integrated Ka-band receiver front end, containing p-i-n-s.t.c, mixer and local oscillator. Fin-line couplers necessary for other integrated circuits have shown coupling factors up to crossover operation with full waveguide bandwidth.