5G 6G communication CMOS Deep Belief Network E-band G-band broadband amplifiers GaAs IoT devices MEMS MIMO THz communications Terahertz-band Wi-Fi artificial noise beam scattering channel emulator communication and sensing cyclic prefix interval (CPI) dual-band folded waveguide four-ports junction field-effect transistor low noise millimeter-wave multiband detector multiple eavesdroppers multiple input–multiple output (MIMO) multiple-input multiple-output n/a octagonal ring antenna