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- 2019
- split rings structure
- metamaterial
- triple band
- terahertz (THz)
- absorber
- Optoelectronic Information Science and Engineering
- Urmia University
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A 128-Pixel System-on-a-Chip for Real-Time Super-Resolution Terahertz Near-Field Imaging
摘要： This paper presents a fully integrated system-on-a-chip for real-time terahertz super-resolution near-field imaging. The chip consists of 128 sensing pixels with individual cross-bridged double 3-D split-ring resonators arranged in a 3.2 mm long 2 × 64 1-D array. It is implemented in 0.13-μm SiGe bipolar complementary metal–oxide–semiconductor technology and operated at around 550 GHz. All the functions, including sensor illumination, near-field sensing, and detection, are co-integrated with a readout integrated circuit for real-time image acquisition. The pixels exhibit a permittivity-based imaging contrast with a worst case estimated relative permittivity uncertainty of 0.33 and 10–12-μm spatial resolution. The sensor illumination is provided with on-chip oscillators feeding four-way equal power divider networks to enable an effective pixel pitch of 25 μm and a dense fill factor of 48% for the 1-D sensing area. The oscillators are equipped with electronic chopping to avoid 1/f-noise-related desensitization for the SiGe-heterojunction bipolar transistor power detectors integrated at each pixel. The chip features both an analog readout mode and a lock-in-amplifier-based digital readout mode. In the analog readout mode, the measured dynamic range (DR) is 63.8 dB for a 1-ms integration time at an external lock-in amplifier. The digital readout mode achieves a DR of 38.5 dB at 28 f/s. The chip consumes 37–104 mW of power and is packaged into a compact imaging module. This paper further demonstrates real-time acquisition of 2-D terahertz super-resolution images of a nickel mesh with 50-μm feature size, as well as a biometric human fingerprint.
关键词： terahertz,system-on-a-chip (SoC),SiGe heterojunction bipolar transistor (HBT),split-ring resonator (SRR),near-field array,3-push Colpitts oscillator,super-resolution imaging,near-field scanning optical microscopy (NSOM),power detector
更新于2025-09-09 09:28:46
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Compact Broadband Dipole Antenna with Split Ring Resonators
摘要： A compact broadband low-profile dipole antenna with split ring resonators (SRRs) is presented. The antenna is composed of a conventional dipole element and two SRRs. Each arm of the printed dipole is enclosed by a printed SRR to provide the favorable electromagnetic environment for coupling. Three modes are generated, which interact together to provide broadband characteristics, covering 1.45 GHz to 2.49 GHz (|S11| < ?10 dB bandwidth of 52.79%). The antenna is computationally demonstrated to have broadband characteristics and stable gain with symmetric radiation patterns. The compact antenna with overall dimensions of 10.2 mm × 74.6 mm × 0.508 mm (0.067λo × 0.489λo × 0.0033λo at 1.97 GHz) has a radiation efficiency > 90%. The compact size, simple structure, and stable radiation properties of the antenna increase its suitability for many wireless communication applications.
关键词： broadband,split ring resonators,dipole antenna,compact,wireless communication
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - New Theory for Unmixing ILL-Conditioned Hyperspectral Mixtures
摘要： Hyperspectral unmixing (HU), a blind source separation problem, aims at unambiguiously identifying the spectral signatures of the materials, as well as their abundances, from the measured hyperspectral mixtures. In real hyperspectral scenes, high correlation between the spectral signatures is commonly observed, making HU quite challenging. Although such ill-conditioning is critical for effective HU, it is often ignored in existing HU literature. To the best of our knowledge, existing preconditioning techniques, for reducing the condition number of the signature matrix, were developed based on the pure-pixel assumption, which can, however, be seriously violated in remote sensing. Under a relaxed purity assumption, with respect to the pure-pixel one, this paper proposes novel theory for unmixing ill-conditioned hyperspectral mixtures. Specifically, we exactly identify the John’s ellipsoid (i.e., the maximum ellipsoid inscribed in the convex hull of the hyperspectral data vectors) via split augmented Lagrangian shrinkage algorithm (SALSA), and transform this ellipsoid into an Euclidean ball. This transformation brings the data vectors into a new space wherein the corresponding material signature vectors form a regular simplex, which is a very strong prior information. Based on this prior, we design an HU criterion, and prove its perfect identifiability under a very mild sufficient condition. Then, we demonstrate the feasibility of realizing our criterion via non-convex optimization and guarantee a stationary point solution.
关键词： split augmented Lagrangian shrinkage algorithm,Hyperspectral unmixing,pure-pixel assumption,non-convex optimization,John’s ellipsoid
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Chennai, India (2018.3.22-2018.3.24)] 2018 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET) - Dual-band Bandpass Filter Using Complementary Split Ring Resonators for X-Band Applications
摘要： This paper is focused on Complementary Split Ring Resonator (CSRR) to design a dual band bandpass filter (BPF) for X-Band frequencies using metamaterial concept. To achieve the functionalities of metamaterials, rectangular shaped complementary split ring resonators are etched in the ground plane along with λ/4 microstrip lines on the top. The inner and the outer rings are joined at the center through a gap. The length of the inner ring and the outer ring are calculated to make the BPF operating at 8.2 GHz and 9 GHz in X-Band. The width of the inter-connecting gap is changed to control the passband edges. An equivalent circuit model is proposed for the designed dual-band BPF to understand the working of the basic cell along with a microstrip line. By varying the length and width of the CSRR and changing the microstrip line dimensions two resonances are can be adjusted and finally fixed at our desired resonating frequencies. The results of EM simulation and the circuit simulation are compared to confirm the validity of the proposed design.
关键词： Bandpass filter,Complementary Split Ring Resonators,Dual-band filter,Metamaterials
更新于2025-09-09 09:28:46
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Compressive Hyperspectral Imaging With Spatial and Spectral Priors
摘要： This paper proposes a new compressive hyperspectral imaging method, including the design of a cost-effective distributed sampling (DS) scheme and an efficient reconstruction model. The new sampling scheme, named as distributed separate sampling (DSS), encodes different hyperspectral bands with mutually independent two-dimensional separate sensing operators. Compared with existing DS schemes, DSS reduces lots of resource overhead in the premise of generating measurements with low redundancy. Furthermore, in contrast to the existing DS schemes, DSS keeps the original structure of hyperspectral images (HSIs) during sampling procedure. The new joint reconstruction model, namely, joint nuclear/total variation/L1 norm minimization, exploits both spatial and spectral priors of HSIs. Unlike the other joint reconstruction models, the proposed model utilize an L1 -based distance function to measure the similarity between adjacent bands, which improves the recovery quality of HSIs. Besides, we develop a new compressive inversion algorithm under the split Bregman framework, which is of low computational complexity, to solve our proposed reconstruction model. Comprehensive experimental results demonstrate the efficiency of our method.
关键词： Compressive hyperspectral imaging (CHI),split Bregman,joint reconstruction,distributed sampling (DS)
更新于2025-09-09 09:28:46
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High-performance interactive analysis of split aptamer and HIV-1 Tat on multiwall carbon nanotube-modified field-effect transistor
摘要： Interaction between split RNA aptamer and the clinically important target, HIV-1 Tat was investigated on a biosensing surface transduced by functionally choreographed multiwall carbon nanotubes (MWCNTs). Acid oxidation was performed to functionalize MWCNTs with carboxyl functional groups. X-ray photoelectron spectroscopy analysis had profound ~2.91% increment in overall oxygen group and ~1% increment was noticed with a specific carboxyl content owing to C=O and O–C=O bonding. The interaction between split RNA aptamer and HIV-1 Tat protein was quantified by electrical measurements with the current signal (Ids) over a gate voltage (Vgs). Initially, 34.4 mV gate voltage shift was observed by the immobilization of aptamer on MWCNT. With aptamer and HIV-1 Tat interaction, the current flow was decreased with the concomitant gate voltage shift of 23.5 mV. The attainment of sensitivity with split aptamer and HIV-1 Tat interaction on the fabricated device was 600 pM. To ensure the genuine interaction of aptamer with HIV-1 Tat, other HIV-1 proteins, Nef and p24 were interacted with aptamer and they displayed the negligible interferences with gate voltage shift of 3.5 mV and 5.7 mV, which shows 4 and 2.5 folds lesser than HIV-1 Tat interaction, respectively.
关键词： Field effect transistor,Multiwall carbon nanotube,Split aptamer,HIV-1 Tat
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Advances in Computing, Communications and Informatics (ICACCI) - Bangalore, India (2018.9.19-2018.9.22)] 2018 International Conference on Advances in Computing, Communications and Informatics (ICACCI) - Compact Tunable Dual-band Bandpass Filter using Edge-open Split Ring Resonators for X-Band Applications
摘要： In this paper, a dual-band bandpass ?lter(BPF) is designed using edge-open Split Ring Resonators(SRR) which is obtained by modifying the conventional SRRs. The inner ring and the outer ring of the edge-open SRRs are connected to stubs to get dual passbands with improved ?lter characteristics. The rings of the SRR are loaded with varactor diodes to tune the individual passbands of the proposed BPF. The ?rst passband can be tuned independently by varying the capacitance of the varactor diode D1 while the second passband remains unchanged by ?xing the capacitance of the varactor diode D2 and vice versa. Hence, the proposed ?lter helps in tuning both the passbands independently of about 0.6GHz for the ?rst passband & 0.3GHz for the second passband and achieves compactness in size of about 20mm x 14mm. The ring equivalents of each rings and the obtained S-parameter results of the proposed BPF while tuning the individual passbands are discussed in this paper.
关键词： Split Ring Resonators,Varactor Diodes,Tunable ?lter,Metamaterials,Dual band bandpass ?lter
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Bayesian Super-Resolution Method for Forward-Looking Scanning Radar Imaging Based on Split Bregman
摘要： In forward-looking scanning radar imaging, the azimuth resolution can be improved by adding the sparse constraint. However, the azimuth resolution is limited with noise influence by traditional sparse regularization methods. In this paper, we propose a Bayesian super-resolution method that solves the L1 regularization problem using the split Bregman algorithm. This method decouples L1 and L2 norms for the independence of them to reduce the computational complexity. The simulations verify that the proposed algorithm provides a better resolution and de-noising ability compare with conventional methods.
关键词： sparse constraint,super-resolution,split Bregman,Forward-looking imaging
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Study on Efficient High Frequency Method of Electromagnetic Scattering of Electrically Large Target
摘要： In this paper, a new method based on SBR method is proposed to calculate the electromagnetic scattering problem of electrically large target. In traditional SBR method, the split size is usually less than 0.4 wavelength to ensure the accuracy. In this paper, the split size which could describe the shape of the target is enough. So the calculating memory and time can be reduced greatly. And the parallel technology is utilized to further accelerate the speed of the program.
关键词： electromagnetic scattering,parallel technology,split size,SBR
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Radio and Antenna Days of the Indian Ocean (RADIO) - Mauritius (2018.10.15-2018.10.18)] 2018 IEEE Radio and Antenna Days of the Indian Ocean (RADIO) - Circular SRR Shaped UWB Antenna with WiMAX Band Notch Characteristics
摘要： A Compact ultra-wideband microstrip patch antenna with single notch characteristics is proposed in this paper. The proposed antenna comprises of a split ring resonator (SRR) and an open loop rectangular resonator (OLRR). The split ring resonator in this paper plays a dual role, it acts as a radiating patch and also as a band rejecter to eliminate the entire worldwide interoperability for microwave access (WiMAX) covers 3.3 GHz – 3.6 GHz band. OLRR is used for the suppression of the harmonic frequency band notch. The compact size of the antenna is 36 × 30 mm2.
关键词： Split Ring Resonator (SRR),WiMAX band notch,Open Loop Rectangular Resonator (OLRR),Ultra-wideband (UWB)
更新于2025-09-04 15:30:14