Yuh-Jing Hwang

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Design and cryogenic operation of an intermediate frequency (IF) low noise amplifier using a 0.15-µm InGaAs mHEMT process for Atacama Large Millimeter/Submillimeter Array (ALMA) is presented in this paper. The amplifier covers 4–12 GHz with small signal gain of 27±2 dB and effective noise temperature of 18–25 K when operating at(More)
a W-band subharmonically pumped (SHP) diode mixer module is designed, fabricated and tested for broadband astronomical applications. The packaged module performance is measured and compared under room-temperature and cryogenic environment. In summary, compared to the room-temperature performance, when the SHP diode mixer is operated under cryogenic(More)
A simple E-plane waveguide-to-microstrip transition probe on quartz substrate is designed. Instead of using cascaded microstrip sections as impedance transformer, the transition probe adopting the structure analogous to monopole antenna with sleeve features a compact structure and tunable bandwidth. The sleeve contributes an additional resonant mode to(More)
We demonstrate an in vivo transmission T-ray mammography for early breast cancer detection in an animal model. Compared to the state-of-the-art sensitivity of X-ray mammography (Volume: 4.22mm<sup>3</sup>), T-ray achieved much earlier cancer detection (Volume: 0.5mm<sup>3</sup>).
A phase-locked broadband GaAs HBT voltage controlled oscillator module is designed, fabricated and tested for the local oscillators in millimetre-wave astronomical heterodyne receivers. The configuration of the local oscillator module is based on the offset phase-locked loop scheme with frequency dividing circuit in the feedback path. Employing closed-loop(More)
A near-field phasor beam measurement system is developed for the characterization of heterodyne receiver optics at submillimeter-wave frequencies. The system synthesizes a pair of submillimeter-wave signals as the RF and local oscillator (LO) sources from common reference sources. The synthesized harmonic numbers of the RF and LO sources are arranged with(More)
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