—Recent changes in how people consume multimedia services are causing an explosive increase in mobile traffic. With more and more people using wireless networks, the demand for the ultra-fast wireless communications systems is increasing. To date, this demand has been accommodated with advanced modulation schemes and signal-processing technologies at… (More)
We demonstrate direct quadrature modulator and demodulator monolithic microwave integrated circuits for future terahertz communications at 300 GHz based on the quadrature phase-shift keying (QPSK) modulation format. For the modulating and demodulating signal, we employed half-Gilbert cell mixers, which provide balanced signaling and moderate performance in… (More)
In this paper, we present a microwave photonic technique to produce a noise signal from the microwave to sub-terahertz region with an optical amplified spontaneous emission noise, optical filter, and photodetector. With this scheme, it is easy to control the noise level by simply controlling the input optical noise power. In addition, the output noise… (More)
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This paper presents a module for a 300-GHz, 20-Gbps amplitude-shift keying (ASK) transmitter using monolithic microwave integrated circuits (MMICs) based on 80-nm-gate InP high-electron-mobility-transistor (InP-HEMT) technology. The MMICs consist of a power amplifier and modulator circuit. Output power of 9.5 dBm at 300 GHz was achieved in the power… (More)
We present a direct quadrature modulator MMIC based on InP HBTs for generating QPSK signals at 300 GHz. The modulator consists of two single balanced mixers and passive baluns and couplers. In this work, two different transmission line structures - thin-film microstrip lines and inverted microstrip lines - were simultaneously utilized in the single chip for… (More)
A 300-GHz planar microstrip-to-waveguide transition in low-temperature co-fired ceramic (LTCC) is numerically and experimentally analyzed. A via fence and air holes are used to form a three-dimensional transition structure and a vertical hollow waveguide inside the multilayer LTCC substrate. The transition consists of a coplanar-waveguide-fed slot radiator… (More)