Current Issue : April-June Volume : 2026 Issue Number : 2 Articles : 5 Articles
Time-division duplex (TDD) transceivers have found broad utility in millimeter-wave 5G communication, radar and imaging applications. The co-design of the switch and transmit/receive (T/R) amplifiers becomes essential in optimizing the passive loss and chip size. This work presents a Ka-band T/R amplifier with an embedded switch topology. The amplification cores from the TX and RX channels reuse the matching network to the T/R common port, and the full combination of switching and matching structures is enabled within a compact two-winding transformer. Implemented in 40 nm CMOS technology, the proof-of-concept Ka-band T/R amplifier occupies a core chip area of 0.163 mm2. Experimental results show that it achieves a peak gain of 17.2 dB with a −3 dB bandwidth of 22.6–30.2 GHz in TX mode and a peak of 17.1 dB with a −3 dB bandwidth of 23.4–31.0 GHz in RX mode. The compact size and wideband gain response make the proposed T/R amplifier suitable for Ka-band TDD applications....
Low-dropout regulators (LDOs) are critical modules in aerospace electronic systems. However, they are susceptible to single-event transient effects, which can impact the stability of the power system. Currently, almost all aerospace LDOs employ analog design to achieve robust output current characteristics. In this paper, three LDO architectures including analog LDO, digital LDO, and hybrid LDO are investigated, and a novel multi-loop hybrid LDO featuring analog proportional and digital integral control is proposed. A load detection module is introduced to allow the analog loop to operate independently under light-load conditions, thereby eliminating limit cycle oscillation (LCO) issues. In addition, a falling edge detection module is implemented to accelerate the transient response of the circuit. Three LDO circuits are designed using a 28 nm CMOS process, and their single-event transient responses are compared using double-exponential current pulse simulations. The results show that the proposed hybrid LDO exhibits the strongest transient response and best immunity to single-event effects under heavy-load conditions, achieving an efficiency of 99.975%....
Gallium Nitride (GaN) fabricated on an insulated sapphire substrate achieves a higher rated voltage of monolithic power integrated circuits compared to that fabricated on a conductive silicon substrate. In this paper, the effectiveness of isolation approaches considering substrate bias and crosstalk effects between adjacent devices in GaN-on-Sapphire monolithic power integrated circuits is investigated. It is demonstrated that the substrate bias and crosstalk effects between high-side and low-side power devices are effectively suppressed regardless of substrate termination with the implantation isolation approach. Thanks to the ultrathin buffer upon an insulated sapphire substrate, the ion implantation can also isolate the adjacent high-voltage (power) and low-voltage (logic) devices. However, a weak crosstalk effect that is caused by capacitive coupling is still observed between high-voltage devices and low-voltage devices with the implantation approach; the degradation rate is calculated to be up to 3%. Experimental results prove that a shallow trench isolation structure in the implantation region can be adopted to mitigate the crosstalk effects, to further improve the stability of integrated logic circuits and drivers under dynamic high-voltage switching conditions....
Silica-based spliers, couplers, and arrayed waveguide gratings are key components in optical communication. However, the high tuning power consumption of silica chips limits their development and application in elds such as Recongurable Optical Add/Drop Multiplexers and Mode Division Multiplexing. In this work, we demonstrate a silica thermo-optic switch based on polymer cladding within a Mach–Zehnder Interferometer framework, in which a UV-curable polymer is employed as the upper cladding to enhance thermal eciency. The device exhibits a power consumption of 48 mW, rise and fall response times were 215 μs and 271 μs, compared to all-silicon switches, the power consumption is reduced by 75%, and the switching speed is improved by nearly a factor of two, while maintaining a comparable insertion loss. Experimental results demonstrate an insertion loss of 8.53 dB and an extinction ratio of 10.12 dB....
This work presents a monolithically integrated short-wavelength infrared (SWIR) image sensor based on indium arsenide (InAs) quantum dot photodiodes (QDPDs). The thin-film photodiode (TFPD) architecture enables direct integration on silicon readout integrated circuits (ROICs), eliminating wafer-to-wafer bonding and providing a scalable, RoHS-compliant alternative to lead-based colloidal quantum dot (CQD) devices. The proposed 3T pixel design incorporates dual conversion gain (DCG), enabling wide dynamic range imaging. The fabricated prototype achieves external quantum efficiencies of 28% at 1200 nm and 4.8% at 1400 nm, together with a dynamic range of 83.5 dB. A frame-based digital correlated double sampling (CDS) scheme stores the reset level in the digital domain and subtracts it after integration, thereby suppressing reset kTC noise and mitigating random telegraph signal (RTS) noise. Imaging demonstrations highlight SWIR-specific functionalities, including material discrimination, imaging through smoke, and transmission through silicon wafers. A performance comparison with previously reported SWIR pixels further confirms the competitiveness of the proposed InAs QDPD imager. These results establish InAs QDPDs as a promising platform for next-generation SWIR imaging, combining high sensitivity, extended spectral coverage, and scalable integration....
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