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We developed a 0.1‐μm metamorphic high electron mobility transistor and fabricated a W‐band monolithic microwave integrated circuit chipset with our in‐house technology to verify the performance and usability of the developed technology. The DC characteristics were a drain current density of 747 mA/mm and a maximum transconductance of 1.354 S/mm; the RF characteristics were a cutoff frequency of 210 GHz and a maximum oscillation frequency of 252 GHz. A frequency multiplier was developed to increase the frequency of the input signal. The fabricated multiplier showed high output values (more than 0 dBm) in the 94 GHz–108 GHz band and achieved excellent spurious suppression. A low‐noise amplifier (LNA) with a four‐stage single‐ended architecture using a common‐source stage was also developed. This LNA achieved a gain of 20 dB in a band between 83 GHz and 110 GHz and a noise figure lower than 3.8 dB with a frequency of 94 GHz. A W‐band image‐rejection mixer (IRM) with an external off‐chip coupler was also designed. The IRM provided a conversion gain of 13 dB–17 dB for RF frequencies of 80 GHz–110 GHz and image‐rejection ratios of 17 dB–19 dB for RF frequencies of 93 GHz–100 GHz.

In this paper, a W-band mixer integrated circuit (IC) with high image rejection ratio (IRR) is presented, compensating for the amplitude and phase mismatches between the I and Q channels in the image rejection mixer (IRM) using RF buffer amplifiers. It is shown by analysis and simulation that the signal coupling between the I and Q channels in the IRM can generate mismatches which can severely degrade the IRR, even though other circuit components are symmetrically designed so as not to induce mismatches. The coupling between two channels can become serious, especially in millimeter-wave IRM ICs where the circuit components are laid out in close proximity to reduce the chip size. It is also shown that poor isolation of millimeter-wave couplers can seriously degrade IRR. In this work, we employ an RF buffer amplifier at the RF port of the resistive mixer to compensate for the amplitude and phase mismatches. The designed W-band IRM IC is fabricated in a 0.1-μm GaAs pHEMT process. Measurements show that the bias tuning of the RF buffer amplifiers can minimize the mismatches and improve the IRR by up to 35 dB at RF from 91 to 95 GHz at an IF of 50 MHz. The IRM exhibits an IRR of 19.2-47.9 dB with conversion loss of 7.9-9.2 dB, which belongs to the highest IRR among the reported IRMs in the W-band.

In this paper, a high-power amplifier integrated circuit (IC) in gallium-nitride (GaN) on silicon (Si) technology is presented at a W-band (75–110 GHz). In order to mitigate the losses caused by relatively high loss tangent of Si substrate compared to silicon carbide (SiC), low-impedance microstrip lines (20–30 Ω) are adopted in the impedance matching networks. They allow for the impedance transformation between 50 Ω and very low impedances of the wide-gate transistors used for high power generation. Each stage is matched to produce enough power to drive the next stage. A Lange coupler is employed to combine two three-stage common source amplifiers, providing high output power and good input/output return loss. The designed power amplifier IC was fabricated in the commercially available 60 nm GaN-on-Si high electron mobility transistor (HEMT) foundry. From on-wafer probe measurements, it exhibits the output power higher than 26.5 dBm and power added efficiency (PAE) higher than 8.5% from 88 to 93 GHz with a large-signal gain &gt, 10.5 dB. Peak output power is measured to be 28.9 dBm with a PAE of 13.3% and a gain of 9.9 dB at 90 GHz, which corresponds to the power density of 1.94 W/mm. To the best of the authors’ knowledge, this result belongs to the highest output power and power density among the reported power amplifier ICs in GaN-on-Si HEMT technologies operating at the W-band.

In this letter, a quasi-coaxial through-silicon-via (TSV) is presented for millimeter-wave integrated circuit (IC) packaging. The quasi-coaxial-via (Q-COV) structure in which one side ground metal is removed can minimize the interconnect length when it is mounted, in comparison to the coaxial-via (COV) structure. Simulation analysis shows that the Q-COV has similar electrical characteristics as the COV up to 100 GHz even though there is no GND on one side. To make the small signal core of the Q-COV, the silicon-core metallization process was used and a Si-interposer with Q-COVs of 50- $\mu \text{m}$ core diameter was fabricated and mounted on the glass board for signal transition analysis. The measured transition loss in the mounted Si-interposer was very small, only about 0.6 dB at 100 GHz, and the return loss was more than 20 dB for the entire measured frequency band (0–110 GHz).

This paper reports the interconnection design and analysis of the embedded IC package. Instead of real chips, we used a dummy chip made of silicon. Dummy chip is GCPW structure and chip's lower ground is not in the chip back but below 20 μm polymer. The thickness of dummy IC is 100 μm and the depth of the cavity is 110 μm. An organic lamination process fills the gap between the inserted chip and the cavity and forms a flat insulating layer. The interconnection for the two inserted dummy ICs was realized using the patterning process, with a very short length of 400 μm. By forming sufficient via holes, the parasitic resonance caused by the cavity is minimized. As a result, the loss of the interconnection is less than 0.25 dB and return loss is more than 30 dB at all measured frequency.

UNLABELLED Accurate and rapid analytical methods are essential for the detection and identification of biological warfare agents (BWA). Although various studies have investigated the use of MALDI-TOF MS for bacterial classification, only a few studies have examined the applicability of method for the identification of BWAs. This study aimed to generate, collect and analyse Bacillus spore aerosol particles of 2-10 μm, the optimal size of a BWA. Bacillus spore aerosol particles of 2-10 μm were rapidly analysed using direct in situ MALDI-TOF MS without pretreatment processes. A mass spectrum of Bacillus spore aerosol particles was successfully detected. For real-time detection and identification, a mass spectral database of Bacillus spores was constructed, and an algorithm was developed and applied. Bacillus spore particles were rapidly detected and identified by MS, which can be used for the detection and inspection of BWAs. SIGNIFICANCE AND IMPACT OF THE STUDY Methods that permit accurate and fast detection and identification are essential in the case of pathogens such as Bacillus anthracis, which can be used as biological warfare agents or bioterrorism materials. Here, direct in situ MALDI-TOF MS allowed the high-throughput detection and identification of aerosolized Bacillus spore particles, and this method could be effectively applied for the detection and inspection of BWAs. In this context, we believe that this method may contribute to the realization of real-time and on-site identification of BWAs.