access accuracy accurate active adaptive advanced advances algorithm amplifier amplifiers analysis angle antenna antennas antipodal applications approach arbitrary array arrays arrival assessment backed bandpass bandwidth based biometric branch branched cardiac cavity center ceramic characteristics characterization circuit cofired combiner combiners compact compatible components compound compressed compressing compressive concept concepts concrete conical contacts continuous corrugated coupler coupling critical cross cylindrical dense deposition design detection development device devices dielectric difference dimensional directional discrete distributed divider domain doppler dynamic effect effects efficiency efficient eight electronic element elliptical embedded enabling enhancement environment environments estimation experiment experimental feasibility ferrimagnetic films filter filters folded formed framework frequency garnet generator ground guidelines hardware heartbeat heartbeats hemts higher highly hollow holographic human imaging implementation implemented implementing improved impulse indoor integrated integration intelligent invasive investigation issues joint junction laptop layer leading level limitation lines localization lossy mapping matching meander measurement measurements medical metal method micro microdoppler microstrip microwave millimeter miniature minimal mobile modeling modified module monitoring monopole moving multi multiband multifunctional multilayer multiple multiplexers multiradio narrow navigation nested network noise noncoherent noncontact nonreciprocal novel ohmic operating oriented oscilloscope output parameters passive patch patches patterned patterns people performance person persons phase phased planar platform platforms polarization portable positioning power prediction pressure processing profile properties protruded pulse radar radial radios range rapidly rates ratio receiver receivers recent recognition reconfigurable reconstruction refresh representation resistance respiration respiratory sampler sampling scheme sensing sensor sequential service short signal signatures silicon simplified simulation simultaneous single slotted space speed split splitter sputter state stepped structure subject substrate substrates superconducting superconductor superconductors surface surgical switch switchable switches symmetric synthesis system systems tapered technology temperature theory thick three through times towards tracking transition transmission trends twisted ultra universal using utilizing variations vital vivaldi waveguide waveguides wideband wireless yba2cu3o7