摘要：This paper presents a systematic investigation and demonstration of a K-band circularly polarized liquidcrystal-based phased array(LCPA),including the design,over-the-air(OTA)in-array calibration,and experimental *** LCPA contains 16 phase-shifting radiating channels,each consisting of a circularly polarized stacked patch antenna and a liquid-crystal-based phase shifter(LCPS)based on a loaded differential line *** to its slow-wave properties,the LCPS exhibits a maximum phase-shifting range of more than 360°with a figure of merit of 78.3(°)·dB^(-1)based on a liquid crystal layer with a thickness of only 5μ***,an automatic OTA calibration based on a state ergodic method is proposed,which enables the extraction of the phase-voltage curve of every individual LCPA *** proposed LCPA is manufactured and characterized with a total profile of only 1.76 mm,experimentally demonstrating a scanned circularly polarized beam from-40°to+40°with a measured peak gain of 12.5 dBic and a scanning loss of less than 2.5 *** bandwidth of the LCPA,which satisfies the require-ments of port reflection(|S_(11)|)<-15 dB,an axial ratio(AR)<3 dB,beam squinting<3°,and a gain variation<2.2 dB,spans from 25.5 to 26.0 *** total efficiency is about 34%,which represents a new state of the *** use of the demonstrated low-profile LCPA to support circularly polarized scanning beams,along with the systematic design and calibration methodology,holds potential promise for a variety of millimeter-wave applications.

摘要：83-nm T-shaped gate InP-based In0.52Al0.48As/In0.65Ga0.35As pseudomorphic high electron mobility transistors （PHEMTs） with excellent DC and RF performance as well as low noise characteristics are reported, including a maximum saturation current density/ass of 894 mA/mm, a maximum extrinsic transconductance gm, max of 1640 mS/mm, an extrapolated cutoff frequency ft of 247 GHz and a maximum oscillation frequency fmax of 392 GHz which were based on the measured S-parameters from 1 to 110 GHz. The minimum noise figure （NFmin） measured by the cold-source method is 1 dB at 30 GHz associated with a gain of 14.5 dB at Vds of 0.8 V and Ids of 17 mA. These results were obtained by the combination of increased InAs mole fraction in the channel, gate size scaling, parasitic reduction and the quantization channel. These excellent results make it one of the most suitable devices for millimeter wave （MMW） low noise applications.

摘要：90-nm T-shaped gate InP-based In_（0.52）Al_（0.48）As/In_（0.6）Ga_（0.4）As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2×30 μm,a source-drain space of 2.5 μm,and a source-gate space of 0.75 μ***,RF and small-signal model characterizations were *** maximum saturation current density was measured to be 755 mA/mm biased at V_（gs）=0.6 V and V_（ds）=1.5 *** maximum extrinsic transconductance was measured to be 1006 mS/mm biased at V_（ds）=—0.1V and V_（ds）=1.5 *** extrapolated current gain cutoff frequency and maximum oscillation frequency based on S-parameters measured from 0.5 to 110 GHz were 180 and 264 GHz,*** inflection point（the stability factor k=1）where the slope from-10 dB/decade（MSG） to-20 dB/decade（MAG） was measured to be 83 *** smallsignal model of this device was also established,and the S-parameters of the model are consistent with those measured from 0.5-110 GHz.