- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A High-Resolution 220-GHz Ultra-Wideband Fully Integrated ISAR Imaging System
摘要： In this paper, an ultra-wideband fully integrated imaging radar at sub-terahertz (sub-THz) frequencies is presented, which demonstrates a fine lateral resolution without using any focal lens/mirror. We have achieved a lateral resolution of 2 mm for an object at 23-cm distance as well as a range resolution of 2.7 mm. To achieve the decent range resolution, in a frequency modulation continuous wave radar configuration, a state-of-the-art chirp bandwidth (BW) of 62.4 GHz at a center frequency of 221.1 GHz is generated and efficiently radiated. We have presented a design technique for the optimal design of the passive embedding around the core transistor to maximize the tuning BW of the voltage controlled oscillator. At the receiver side, to maximize the intermediate frequency level, a subharmonic mixer is utilized, which is designed for the lowest conversion loss. Finally, to obtain the fine lateral resolution, we have implemented near-field beamforming algorithm based on the inverse synthetic aperture radar (ISAR) systems. The synthesized beamwidth is less than 0.5°; hence, high-resolution images are reconstructed. The system is fabricated in a 55-nm BiCMOS process. To the best of our knowledge, this is the first imaging radar at THz/sub-THz frequencies, which utilizes ISAR to achieve a high lateral resolution while the radar system is fully integrated.
关键词： ultra-wideband,Frequency modulation continuous wave (FMCW),remote sensing,THz,radar,sub-terahertz (sub-THz),oscillator,inverse synthetic aperture radar (ISAR),plane wave
更新于2025-09-23 15:21:21
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Vacuum Arc Plasma Heated by Sub-Terahertz Radiation as a Source of Extreme Ultraviolet Light
摘要： This paper presents the results of the ?rst experimental studies of the interaction of a powerful sub-terahertz radiation with expanding highly inhomogeneous plasma of vacuum arc discharge. The tantalum plasma of a vacuum arc discharge additionally heated by the focused sub-terahertz radiation of a gyrotron, the radiation power is up to 250 kW, and the wavelength is 1.2 mm. Characteristics of the light emission in the extreme ultraviolet range are presented.
关键词： gyrotron,vacuum arc plasma,Extreme ultraviolet light,sub-terahertz radiation
更新于2025-09-23 15:21:01
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Analysis of a single-mode waveguide at sub-terahertz frequencies as a communication channel
摘要： We study experimentally the transmission of an electromagnetic waveguide in the frequency range from 160 to 300 GHz. Photo-mixing is used to excite and detect the fundamental TE10 mode in a rectangular waveguide with two orders-of-magnitude lower impedance. The large impedance mismatch leads to a strong frequency dependence of the transmission, which we measure with a high-dynamic range of up to 80 dB and with high frequency-resolution. The modified transmission function is directly related to the information rate of the waveguide, which we estimate to be about 1 bit per photon. We suggest that the results are applicable to a Josephson junction employed as a single-photon source and coupled to a superconducting waveguide to achieve a simple on-demand narrow-bandwidth free-space number-state quantum channel.
关键词： communication channel,TE10 mode,sub-terahertz frequencies,Josephson junction,impedance mismatch,superconducting waveguide,single-photon source,waveguide
更新于2025-09-23 15:19:57
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High-Gain Metasurface in Polyimide On-Chip Antenna Based on CRLH-TL for Sub-Terahertz Integrated Circuits
摘要： this paper presents a novel on-chip antenna using standard cMoS-technology based on metasurface implemented on two-layers polyimide substrates with a thickness of 500 μm. the aluminium ground-plane with thickness of 3 μm is sandwiched between the two-layers. concentric dielectric-rings are etched in the ground-plane under the radiation patches implemented on the top-layer. the radiation patches comprise concentric metal-rings that are arranged in a 3 × 3 matrix. The antennas are excited by coupling electromagnetic energy through the gaps of the concentric dielectric-rings in the ground-plane using a microstrip feedline created on the bottom polyimide-layer. the open-ended feedline is split in three-branches that are aligned under the radiation elements to couple the maximum energy. in this structure, the concentric metal-rings essentially act as series left-handed capacitances CL that extend the effective aperture area of the antenna without affecting its dimensions, and the concentric dielectric rings etched in the ground-plane act as shunt left-handed inductors LL, which suppress the surface-waves and reduce the substrates losses that leads to improved bandwidth and radiation properties. The overall structure behaves like a metasurface that is shown to exhibit a very large bandwidth of 0.350–0.385 THz with an average radiation gain and efficiency of 8.15dBi and 65.71%, respectively. It has dimensions of 6 × 6 × 1 mm3 that makes it suitable for on-chip implementation.
关键词： metasurface,integrated circuits,on-chip antenna,polyimide substrate,sub-terahertz
更新于2025-09-19 17:13:59
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Sub-terahertz Quantum-cascade Laser Source based on Difference-frequency Generation
摘要： Authors report a sub-terahertz monolithic semiconductor source based on a high power, long-wavelength quantum cascade laser. In order to obtain higher nonlinear susceptibility in the sub-terahertz frequency region, we design long wavelength dual-upper-state active region in which transition dipole moments are substantially increased. A fabricated device with distributed feedback grating produces nearly watt-level infrared output power, and as a result, it exhibits a peak output power of 18.5 μW at room temperature, around a frequency of ~700 GHz. Besides, the device produces an output power of 103 μW at 110 K.
关键词： dual-upper-state active region,monolithic semiconductor source,difference-frequency generation,sub-terahertz,quantum-cascade laser
更新于2025-09-16 10:30:52
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Research of Volume Free-Electron Laser with Photonic Crystal Structure for Operation in Sub-Terahertz Range
摘要： In this work, we present the results of the numerical optimization of volume free-electron laser based on the interaction between an electron beam and periodic structure of microwave photonic crystal. The optimization aims at the advancement of such device to the sub-terahertz frequency range. We show that the reduction of characteristic geometric dimensions allows increasing the working frequency of photonic crystal fundamental mode up to 12.5 GHz. Moreover, we observe the possibility to generate microwaves at the fifth harmonic of the fundamental frequency, namely f=62.5 GHz and obtain an output power level of about 3.6 kW.
关键词： electron beam,numerical optimization,sub-terahertz,volume free-electron laser,photonic crystal
更新于2025-09-16 10:30:52
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Optimized uni-traveling carrier photodiode and mushroom-mesa structure for high-power and sub-terahertz bandwidth under zero- and low-bias operation
摘要： In this paper, physically-based simulations are carried out to investigate and design uni-traveling carrier photodiode (UTC-PD) for high-power sub-terahertz wave generation at zero- and low-bias operation. The reliability of the physically-based simulation is demonstrated by comparing with our experimental result. Both the bandwidth and RF output power of the proposed UTC-PD is significantly improved by careful design the built-in electric field distribution under high-power input. For the optimized UTC-PD with the mesa diameter of 5 μm, its 3dB bandwidth large than 100 GHz even if the photocurrent reaches 6 mA under zero-bias operation. The device can reach a high bandwidth of 92.4 GHz, 105 GHz, and 119.5 GHz under the reverse bias of 0.5 V, 1 V, and 2 V, respectively, even the input photocurrent as high as 18.2 mA. The peak output-power of the device has enhanced at least 7 dB even at 170 GHz and zero- or low-bias operation. Besides, a novel design of mushroom-mesa UTC-PD (MM-UTC-PD) is proposed which with 4.3% improved high-speed performance. The MM-UTC-PD can trade-off between the external quantum-efficiency and bandwidth when miniaturized junction size is required.
关键词： ultrafast optics,sub-terahertz,optical communications,high-power photodiodes,optical receivers
更新于2025-09-11 14:15:04
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Design of Bias-Free Operational Uni-traveling-Carrier Photodiodes by Transient Simulation for High-power Pulsed Millimeter-Wave Signal Generation in the Sub-THz Regime
摘要： In this paper, bias-free operational uni-traveling-carrier photodiodes (UTC-PDs) for high-power pulsed millimeter-wave signal generation in the sub-terahertz regime are designed and investigated. The reliability of the physics-based transient simulation is first demonstrated by comparing with reported experimental results. Then, the epitaxial layers are analyzed and optimized through transient simulation for bias-free operation and high-power pulsed millimeter-wave signal generation. The performance between original and optimal structure is compared under excitation of pulse train and sinusoidal optical signals. The results show that the peak output power of the modified UTC-PD under 100-GHz, 200-GHz, and 312.5-GHz pulse train excitation is 4.685 dBm, 1.128 dBm, and ? 4.653 dBm, improved by 2.05 dB, 5.15 dB, and 9.36 dB, respectively.
关键词： Bias-free,Optical communication,Millimeter-wave,Transient simulation,Terahertz communications,Sub-terahertz,Uni-traveling-carrier photodiodes (UTC-PD)
更新于2025-09-09 09:28:46