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NOVEL TRANSFORMATION TO DESIGN TRI-BAND FILTERS
摘要： This paper introduces novel derived transformation equations to design Tri-band ?lters. The design utilizes the approach adopted for tri-band bandpass ?lter design based on asymmetric half-wavelength resonator. The obtained optimized ?lter by this approach is used as a reference, and the proposed transformation is applied to calculate the new ?lter design hardware parameters that satisfy its given speci?cations. The reference tri-band ?lter is designed to have: insertion better than 1.3 dB and return loss less than ?10 dB at the resonance frequencies 1.4 GHz, 4 GHz and 5.6 GHz for L-Band DAB, Radar (G-band) and Radar (C-band) applications, respectively. To verify the transformation technique two tri-band ?lters are designed. The ?rst tri-band ?lter is for WVL, WiMAX and WiLAN while the second tri-band ?lter is for UMTS, WiLAN and X-band Satellite applications. The momentum simulations for these ?lters show that the resulting ?lters speci?cations are: the insertion loss is better than 1.3 dB and the return loss is less than ?10 dB at the resonance frequencies 1.3 GHz, 3.6 and 5.7 GHz for the ?rst one. While the insertion loss is better than 1.4 dB and the return loss is less than ?10 dB at the resonance frequencies 1.9 GHz, 5.35 GHz and 8.25 GHz for the second ?lter, respectively. A set of prototype of the ?nal design of the proposed ?lters with optimal parameters was fabricated for experimental veri?cation. The RT 5880 substrate is utilized in this design All the results are obtained using circuit and momentum simulation of the Agilent Design Simulator (ADS) package and the performance characteristics have been measured using the Rohde & Schwarz ZVB20 vector 4 port network analyzer. Analysis and comparison of the obtained results show that all the simulated and the measured results agree well.
关键词： asymmetric half-wavelength resonator,transformation technique,Tri-band ?lters,momentum simulation
更新于2025-09-09 09:28:46
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DUAL-BAND BANDPASS FILTER USING COMPOSITE COUPLING STRUCTURE FOR CPW/MICROSTRIP
摘要： By using a composite coupling structure for coplanar waveguide (CPW)/microstrip, a new dual-band bandpass ?lter (DBBPF) stacking inverted Y-shaped CPW resonators and rectangular ring resonators is proposed. Two resonant frequency bands are simultaneously excited by the CPW feed line. However, it can be convenient to tune individually. Several transmission zeros are realized to improve the selectivity of the ?lter and achieve wide stopband rejection. Good agreement between simulated and measured results demonstrates the validity of this DBBPF.
关键词： rectangular ring resonators,inverted Y-shaped CPW resonators,composite coupling structure,CPW/microstrip,dual-band bandpass filter
更新于2025-09-09 09:28:46
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Band alignment of BiOCl/ZnO core shell nanosheets by X-ray photoelectron spectroscopy measurements
摘要： To improve optoelectronic properties of bismuth oxyhalides, hybrid BiOX photocatalytic materials have draw a great attention, because of the separation of photogenerated electron-hole pairs. The band offset and band alignments are considered as the key parameters to elaborate carrier transport properties in heterojunction. In this paper, to determine the band alignment of BiOCl and ZnO heterostructure, BiOCl/ZnO core shell nanosheets with different thickness of shell layer were synthesized. The valence band offset (VBO or DEV) of BiOCl/ZnO heterostructure was determined using X-ray Photoelectron Spectroscopy measurements. The DEV value of 0.294 § 0.10 eV was calculated by using the Zn 2p3/2, Bi 4f5/2 binding energies as references. Taking the band gaps of 3.37 eV and 3.4 eV for ZnO and BiOCl samples into consideration, respectively, we obtained the type-II band alignment of BiOCl/ZnO heterostructure with a conduction band offset (CBO or DEc) of 0.324 § 0.10 eV.
关键词： X-ray photoelectron spectroscopy (XPS),band offset,BiOCl,ZnO,atomic layer deposition (ALD)
更新于2025-09-09 09:28:46
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Single Band Notched Characteristics UWB Antenna using a Cylindrical Dielectric Resonator and U-shaped Slot
摘要： In this manuscript, a novel hybrid dielectric resonator antenna for ultra wideband (UWB) applications is designed, and single band notched performance is proposed. The circle radiating patch is printed on the FR4 substrate of 1.64 mm thickness and loss tangent tan =0.02, and is fed by the coplanar waveguide. The size of the UWB antenna was minimised to 50–40 mm2. The cylindrical dielectric resonator (CDR) was used to broaden the bandwidth and achieve an impedance bandwidth of more than 113%, covering a frequency range of 3.3 to more than 12GHz. WIMAX band notched characteristics of the antenna to reject (3.2–3.8GHz) were realised by etching a U-shaped slot in the radiating patch. The centre notch frequency can be adjusted from 3.4 to 4.5 GHz by changing the position of the CDR. The band notched characteristics, VSWR, and radiation patterns were studied using the CST microwave simulator and confirmed with the frequency domain ANSOFT high frequency structure simulator (HFSS).
关键词： band-stop function,Cylindrical dielectric resonator (CDR),U-shaped slot,planar monopole
更新于2025-09-09 09:28:46
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Estimation of Pine Forest Height and Underlying DEM Using Multi-Baseline P-Band PolInSAR Data
摘要： On the basis of the Gaussian vertical backscatter (GVB) model, this paper proposes a new method for extracting pine forest height and forest underlying digital elevation model (FUDEM) from multi-baseline (MB) P-band polarimetric-interferometric radar (PolInSAR) data. Considering the linear ground-to-volume relationship, the GVB is linked to the interferometric coherences of different polarizations. Subsequently, an inversion algorithm, weighted complex least squares adjustment (WCLSA), is formulated, including the mathematical model, the stochastic model and the parameter estimation method. The WCLSA method can take full advantage of the redundant observations, adjust the contributions of different observations and avoid null ground-to-volume ratio (GVR) assumption. The simulated experiment demonstrates that the WCLSA method is feasible to estimate the pure ground and volume scattering contributions. Finally, the WCLSA method is applied to E-SAR P-band data acquired over Krycklan Catchment covered with mixed pine forest. It is shown that the FUDEM highly agrees with those derived by LiDAR, with a root mean square error (RMSE) of 3.45 m, improved by 23.0% in comparison to the three-stage method. The difference between the extracted forest height and LiDAR forest height is assessed with a RMSE of 1.45 m, improved by 37.5% and 26.0%, respectively, for model and inversion aspects in comparison to three-stage inversion based on random volume over ground (RVoG) model.
关键词： digital terrain model,complex least squares,P-band polarimetric-interferometric radar (PolInSAR),forest vertical structure
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 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Design and Fabrication of Silicon-cavity Band-pass Filters Based on MEMS Technology
摘要： Microwave filter is an important frequency selective component in communication, radar and other microwave systems, and its performance will directly affect the performance of the whole system. With the miniaturization, lightweight and intelligence of microwave systems, the miniaturization, integration and high performance of filters are the main development targets. This paper introduces the design and fabrication of C-band silicon cavity filters based on the interdigital resonant structure and Microelectromechanical systems (MEMS) fabrication technology. The silicon MEMS cavity filters, with 1/4 wave length interdigital resonators and tapped input and output lines, are designed and fabricated on high-resistivity silicon substrates. The filter is designed by formulas and HFSS simulation. Test results show that, the filter center frequency is 5.6 GHz, the relative bandwidth is 16%, the insertion loss is 2.04 dB, the inhibition at 4.0 GHz and 6.9 GHz is both greater than 40dB, the voltage standing wave ratio (VSWR) is less than 1.30, and the filter chip size is only 7.3 mm×6 mm×0.82 mm. Also, the test results have high consistency with simulation results.
关键词： Microelectromechanical systems (MEMS),Band-pass Filter,Silicon Cavity
更新于2025-09-09 09:28:46
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Fast reconstruction of hyperspectral radiative transfer simulations by using small spectral subsets: application to the oxygen A band
摘要： Hyperspectral radiative transfer simulations are a versatile tool in remote sensing but can pose a major computational burden. We describe a simple method to construct hyperspectral simulation results by using only a small spectral subsample of the simulated wavelength range, thus leading to major speedups in such simulations. This is achieved by computing principal components for a small number of representative hyperspectral spectra and then deriving a reconstruction matrix for a specific spectral subset of channels to compute the hyperspectral data. The method is applied and discussed in detail using the example of top-of-atmosphere radiances in the oxygen A band, leading to speedups in the range of one to two orders of magnitude when compared to radiative transfer simulations at full spectral resolution.
关键词： hyperspectral radiative transfer simulations,oxygen A band,principal component analysis,remote sensing,computational efficiency
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Radar (RADAR) - Brisbane, Australia (2018.8.27-2018.8.31)] 2018 International Conference on Radar (RADAR) - A Simple-Structure FMCW Radar Test System Using PLL-Gunn Oscillator and Fundamental Mixer in 79 GHz Band
摘要： In this study, a simple frequency-modulated continuous wave (FMCW) radar test system for an anti-collision automobile radar in the 79 GHz band has been developed. This system consists of a down-converter based on a fundamental mixer with a phase-locked loop-Gunn oscillator and a mixed domain oscilloscope or a digital oscilloscope. This system can evaluate an FMCW signal in the time domain, which includes the evaluation of the chirp rate, chirp width, chirp length, and linearity. By employing the Gunn oscillator, the down-converter attains a very simple configuration. The down-converter has a conversion gain of 7.8 dB at 79 GHz in typical conditions and a bandwidth of 4 GHz. In this study, we explain the development of the radar test system and demonstrate the same using an FMCW chipset evaluation board.
关键词： Gunn oscillator,E-band,FMCW radar
更新于2025-09-09 09:28:46
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A MINIATURIZED BANDPASS FREQUENCY SELECTIVE SURFACE WITH HIGH SELECTIVITY BASE ON SLOT COUPLING
摘要： A Ku-band bandpass frequency selective surface (FSS) with high selectivity and miniaturization is proposed in this paper. We use two metallic strips and one slot to design the frequency selective surface structure which contains both electrical and magnetic couplings. A metallic via is introduced in the FSS element for miniaturization. With the via inserted at the end of the metallic strip, the FSS unit size is reduced to half compared to that without via inserted. To investigate the operating principle of the slot-coupled FSS, an equivalent-circuit model is given and analysed using the odd- and even-mode method. The constructed out-of-phase signal path causes two transmission zeros (TZs) near the skirts of the narrow pass band, thereby enhancing the selectivity. A prototype of the proposed FSS operating at 16 GHz is fabricated and measured. The measured results agree well with the full-wave and circuit simulation results, thus verifying the FSS design.
关键词： slot coupling,Ku-band,bandpass frequency selective surface,metallic via,high selectivity,equivalent-circuit model,transmission zeros,miniaturization
更新于2025-09-09 09:28:46