Amplifiers; Antennas; Antennas for wireless communications apparatus; Electron tubes; Microwave transmission apparatus for delivering radio programs and messages; Millimeter wave equipment for detecting concealed objects; Oscillators; Radar apparatus; Radar machines and apparatus; Radar receivers with amplifiers; Radio-frequency antennas; Radio-frequency transmitters; Radio frequency generators for supplying radio-frequency energy; Satellite radios; Satellite transmitters and receivers; Vacuu...