- 标题
- 摘要
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- 实验方案
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ICI Cancellation Based on MIMO Decoding for FTN Non-Orthogonal FDM Systems
摘要： In this paper, we investigate multiple-input multiple-output (MIMO) decoding in faster-than-Nyquist non-orthogonal frequency division multiplexing (FTN-NOFDM) for inter-carrier interference (ICI) cancellation. The MIMO decoding is based on depth-first tree search or breadth-first tree search. Sphere decoder (SD) is a commonly used decoding algorithm based on depth-first tree search. Maximum-likelihood detection with QR decomposition and M-algorithm (QRM-MLD) is a commonly used decoding algorithm based on breadth-first tree search. By adding the initial radius to both SD and QRM-MLD, the computational complexity of them can be further decreased without the loss of ICI cancellation performance. In the experiment, SD, QRM-MLD and their corresponding simplified versions are used for ICI cancellation in a 28-Gb/s FTN-NOFDM system with transmission over a 10-km standard single mode fiber. The 3-dB equivalent bandwidth of this system is only approximately 5.5 GHz. Under serious high-frequency distortion caused by limited bandwidth, the bit error rate performance of FTN-NOFDM can still reach the forward error correction limit due to the bandwidth compression and effective ICI cancellation. FTN-NOFDM with 20% and 30% bandwidth savings has approximately 1.3-dB and 1.1-dB improvements in receiver sensitivity compared to FTN-NOFDM with 10% bandwidth savings, respectively. To the best of our knowledge, our work is the first experimental demonstration of depth-first tree search and breadth-first tree search for FTN-NOFDM in a bandwidth-limited optical transmission system. The experimental results show that FTN-NOFDM is a promising scheme for bandwidth-limited systems.
关键词： faster-than-Nyquist non-orthogonal frequency division multiplexing (FTN-NOFDM),Multiple-input multiple-output (MIMO) decoding,bandwidth-limited systems
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Design and Performance Analysis of an UWB Patch Antenna with Enhanced Bandwidth Characteristics
摘要： This paper presents a monopole ultra-wideband (UWB) patch antenna with enhanced bandwidth performance. The reference antenna has a square radiator and fed by a microstrip feed line. The other side of the substrate has a partial ground plane. A trapezoidal slot configuration with proper dimension has been inserted to upper edge of the partial ground plane under the feed line to modify the reference antenna bandwidth characteristics. Additionally, two rectangular shapes have been cut from the edge of the square patch to add another bandwidth improvement. The simulation results prove that the antenna fractional bandwidth of the reference antenna is 122.49 % while for the final antenna model is 147.28 %. The antenna maximum gain, radiation characteristics, radiation efficiency, and group delay characteristics are also investigated.
关键词： monopole antenna,radiation patterns,impedance bandwidth,ultra-wideband
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Electro/Information Technology (EIT) - Rochester, MI (2018.5.3-2018.5.5)] 2018 IEEE International Conference on Electro/Information Technology (EIT) - Hybrid Perturbation Technique Applied to Stacked Patches for Circular Polarization
摘要： In this paper, a wideband circularly polarized (CP) stacked microstrip antenna is presented. CP is achieved by using hybrid perturbation technique, where positive perturbations are applied to the driven patch and negative perturbations to the parasitic patch. The axial ratio bandwidth achieved is wider than that from typical CP patch antennas. The antenna is excited by a probe-feed without requiring any complex dual feed network to generate two equal and orthogonal modes necessary for the CP generation. This reduces the system complexity and saves space in the antenna in comparison to those with dual feeds. The antenna exhibits a simulated impedance bandwidth of (for S11 = -10 dB) 10.4%, and axial ratio (AR ~ 3 dB) bandwidth of 2.8%. The antenna demonstrates broad axial ratio beamwidth in both planes which is useful for wide angular coverage.
关键词： hybrid perturbations,axial ratio bandwidth,stacked patch antenna,Circularly polarized (CP) antennas,microstrip antennas
更新于2025-09-04 15:30:14
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Planar capacitive type humidity sensor fabricated using PTB7-Th by facile solution processing approach
摘要： A capacitive humidity sensor using coplanar electrodes coated with poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl](PTB7-Th) thin film (Al/PTB7-Th/Al) has been fabricated and investigated. In the present work, we show that increased sensitivity is obtained by rough and non-uniform surface morphology of the polymer thin film which comprises distinct peaks and valleys. The sensor shows good sensing behavior with enhanced sensitivity, better linearity and larger bandwidth. The device showed sensitivity over an appreciable range of relative humidity levels (between 20 and 95% RH). Typical adsorption and desorption response times were measured to be 20 s each.
关键词： Sensitivity,Bandwidth,Linearity,PTB7-Th,Solution processing,Capacitive humidity sensor
更新于2025-09-04 15:30:14
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Quasi-Octave Bandwidth In-Phase Three-Layer Platelet Orthomode Transducer Using Improved Power Combiners
摘要： A 64% instantaneous bandwidth turnstile-junction-based orthomode transducer (OMT) made up of only three layers in a platelet configuration is presented. Such frequency coverage, while maintaining a very much reduced number of layers, is accomplished mainly by incorporating an improved power combiner based on noncontacting matching steps machined in one layer. This solution makes a real impact on the compactness concept of these OMTs while maintaining an excellent electrical performance. An OMT in the 10–20-GHz band was designed and measured by obtaining a return loss of 25 dB, an isolation between rectangular ports of 50 dB, a cross-coupling of 45 dB, and an insertion loss below 0.2 dB.
关键词： waveguide,power combiner,orthomode transducer (OMT),platelet,turnstile junction,Octave bandwidth
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Embedded Antenna Design on LoRa Radio for IoT Applications
摘要： This paper presents a miniaturized printed inverted-F antenna (PIFA) embedded on the circuit board of a LoRa sensor node for the internet of things (IoT) applications. On the 1.6 mm-thick board, very limited space is reserved for the antenna deployment, and therefore slots are cut on the ground to reduce operating frequency of the PIFA and create another resonance to broaden the bandwidth. Finally, the proposed antenna is optimized to operate from 402.4 MHz to 441.6 MHz with voltage standing wave ratio (VSWR) less than 3, and its realized gain over the 410-441 MHz LoRa frequency band is higher than -6 dBi.
关键词： internet of things,bandwidth enhancement,LoRa,miniaturized antenna
更新于2025-09-04 15:30:14
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Enhanced absorption of graphene with variable bandwidth in quarter-wavelength cavities
摘要： Quarter-wavelength cavity, as a classical structure for preventing wave re?ection, presents an effective way to enhance the interaction between light and material of ultrathin thickness. In this paper, we propose a method to control the bandwidth of graphene’s enhanced absorption in quarter-wavelength cavity. By varying the spacing distance between graphene and a metallic re?ecting plane, which equals to an odd number of quarter-wavelengths, fundamental and higher order cavity modes are excited, whose ?elds couple to graphene with different spectral bandwidths, leading to bandwidth-controllable absorption in graphene. Absorption ef?ciencies of 9% and 40% are measured for graphene monolayer at 15? and 85? incident angles, respectively. Its absorption bandwidth varies between 52% and 10% of the central wavelength when the spacing distance between graphene and metallic re?ecting plane increases from a quarter wavelength to seven quarter wavelengths. Our ?ndings pave a way in engineering graphene for strong absorption with a controllable bandwidth, which has potential applications in tailoring spectral response of graphene-based optoelectronic devices.
关键词： quarter-wavelength cavity,bandwidth control,enhanced absorption,graphene
更新于2025-09-04 15:30:14