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- 实验方案
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Design of 2 to 18?GHz balanced antipodal Vivaldi antennas using substrate-integrated lenses
摘要： Conventional balanced antipodal Vivaldi antennas (BAVAs) normally have deep ripple levels in E-plane mainlobe region and significant H-plane beamwidth variation over upper frequency band, which are drawbacks for ultra-wideband (UWB) applications. To overcome these issues, this paper introduces two types of lens configurations in front of BAVA. A gradient-index semi-cylindrical lens and a cylindrical lens are employed to improve ripples depth of E-plane mainlobe and broaden H-plane beamwidth, respectively. Both these lenses and BAVA are integrated on the same substrate and the desired refractive indexes of lenses are realized by a combination of a set of air-filled holes in the substrate. Prototypes of the modified BAVA with lenses (BAVA-Ls) are designed, fabricated, and experimentally investigated as well. Measured results show close agreement with simulation. The proposed BAVA-Ls exhibit promising performances such as smaller ripple levels in E-plane mainlobe, wider H-plane beamwidth, higher aperture efficiency, and excellent group delay, while maintaining good bandwidth characteristics over 2 to 18 GHz.
关键词： effective medium theory,dielectric lens,ultra-wideband (UWB),Balanced antipodal Vivaldi antenna (BAVA)
更新于2025-09-23 15:21:01
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Low-profile wideband circularly polarised single-layer metasurface antenna
摘要： A novel low-pro?le single-fed circularly polarised single-layer metasurface antenna for wideband operation is proposed in this Letter. The metasurface antenna consists of nine unit cells arranged in a 3 × 3 layout. Four slits are incorporated into four of them, respectively, to form two orthogonal currents with 90° phase difference; hence, circularly polarised ?elds are excited. Moreover, a modi?ed L-type slot is etched on the middle lattice to improve impedance bandwidth and axial ratio performance. The proposed dielectric-?lled (?r = 3.5, tan δ = 0.001) antenna with a low pro?le of 0.038λ0 (λ0 is the working wavelength at 5.7 GHz in free space) achieves about 18.0% measured ?10 dB impedance bandwidth. The measured 3-dB axial ratio bandwidth of the proposed antenna is about 12.8% (5.35–6.08 GHz) with a broadside gain of more than 6.9 dBi.
关键词： low-profile,metasurface antenna,wideband,circularly polarised,single-layer
更新于2025-09-23 15:21:01
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A Wideband On-Chip Directional Coupler Using a Negative Capacitance Circuit
摘要： We propose a wideband lumped element directional coupler using lossy negative capacitance (NCAP). NCAP provides a broadband resonance effect combined with passive inductors and capacitors in a circuit, enabling the coupler to exhibit wideband directivity performance. In addition, a 3-dB loss in the NCAP enhanced the bandwidth at the expense of the transmission gain, which decreased by only 0.3 dB. The proposed coupler was implemented in the IBM 7RF 180-nm CMOS technology. The size of the core chip is 1180 μm × 570 μm. The designed NCAP provides a capacitance of ?13 pF using a supply voltage of 2.7 V and a current of 9.6 mA. The coupling was designed to be ?10 dB at the center frequency of 1 GHz. The bandwidth was de?ned by the frequency range, which exhibited a directivity of more than 30 dB. The S-parameter measurements showed an absolute bandwidth ranging from 0.86 to 1.12 GHz, and a fractional bandwidth of 26%. In the bandwidth, the coupling had a 0.5-dB variation, the transmission loss was smaller than 2.14 dB, and the noise ?gures were 1.8–2.5 dB.
关键词： Broadband resonance,wideband lumped element (LE) directional coupler,negative capacitance (NCAP)
更新于2025-09-23 15:21:01
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A Simple WiMAX and RFID band Notched UWB Bandpass Filter and It's susceptibility Study
摘要： An ultra-wideband (UWB) bandpass filter (BPF) with a fractional bandwidth (FBW) of about 110%, transmission zero at the high frequency edge, and band notches at the worldwide interoperability for microwave access (WiMAX) and radio frequency identification (RFID) band is presented in this paper. The filter is based on single short-circuited stub, U-shaped defected ground structure (DGS) array, two U-shaped resonators and two stepped impedance resonators (SIRs). The filter is compact and exhibits a selective filtering characteristic equivalent to a 3-pole Chebyshev filter. The design procedure has been described and verified by full-wave electromagnetic (EM) simulation and measurement. The proposed filter has low insertion loss, sharp rejection, and excellent in and out band performance. Due to its applications in WiMAX and RFID systems, the filter may be subjected to high EM radiation from the antenna and nearby sources. Therefore, susceptibility study of such filter is very important. Hence, the susceptibility study of the band notched UWB bandpass filter has been carried out by subjecting the structure to an interference source.
关键词： Microstrip band pass filters (BPFs),notch band,transmission zero,ultra-wideband (UWB) filters
更新于2025-09-23 15:21:01
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Lightweight Broadband Antennas for UAV based GPR Sensors
摘要： In this contribution two different types of broadband antennas namely a logarithmic-periodic dipole antenna (LPDA) and a transversal electromagnetic (TEM) horn antenna for ground penetrating synthetic aperture radar sensors are presented. These antennas are designed to be mounted on an unmanned aircraft vehicle (UAV). The antennas are evaluated in terms of their matching, radiation pattern pulse response and weight. Finally, an integration example of one of these antennas is shown on an UAV.
关键词： ultra wideband antennas,dispersion,unmanned aerial vehicles,Ground penetrating radar
更新于2025-09-23 15:21:01
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A Linear-to-Circular Polarization Conversion Metasurface Based Wideband Aperture Coupled Antenna
摘要： This paper proposes an aperture-coupled antenna with an ultrathin, single-layer metasurface for linear-to-circular (LP–CP) polarization conversion. The unit cell of the metasurface consists of a hexagonal ring surrounded by a square ring printed on both sides of a dielectric substrate for wideband LP-CP conversion. A patch antenna excited by an H-shaped slot aperture uses a 5 × 5 array of the metasurface as a superstrate. Simulated and measured radiation patterns of the proposed antenna are in good agreement. Measured S11 and axial ratio bandwidth of the proposed antenna are 21.5% and 19.23% respectively. Boresight radiation gain is around 10 dBic over 9.5 GHz to 11.5 GHz.
关键词： Circular polarization,Polarization conversion,Metasurface,Aperture coupled antenna,Wideband
更新于2025-09-23 15:19:57
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Wideband absorption in one dimensional bilayer-graphene embedded photonic multilayer structure
摘要： In this article, we propose a one-dimensional graphene-based multilayer structure which composed of traditional dielectric material and graphene. The dependence of absorption characteristics of this structure on the chemical potential of graphene, the optical thickness of the dielectric layer, the loss of the dielectric material and the incident angle are investigated by using the transfer matrix method. It is shown that the absorption bandwidth of the structure can be modulated by the chemical potential of graphene and the absorption is insensitive to the refractive index and geometric thickness of the dielectric material within a certain range. It is also shown that the absorption is generally insensitive to the angle of incidence. These findings have potential applications for designing tunable broadband absorbers and related optoelectronic devices.
关键词： absorption characteristics,wideband absorption,photonic crystals,graphene,transfer matrix method
更新于2025-09-23 15:19:57
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Input Filter Capacitance and Inductance Design for Photovoltaic Systems
摘要： A conformal permeable toroidal antenna operating in both a vertically polarized monopole mode and circularly polarized (CP) dipole mode in the UHF frequency range is designed based on theory of magneto-dielectric radiators. This antenna has been fabricated using a new advanced ferromagnetic laminate composite material whose high impedance and anisotropic properties enable an antenna that radiates via magnetic currents. The antenna, less than 0.5 m in diameter and less than 2 cm thick, was fabricated and tested. Including the imperfections of the feed network and a simple matching scheme, the antenna operates from 200 to 500 MHz with an input match of better than 10 dB, CP dipole realized gain as high as 2 dBi, and monopole mode vertically polarized gain as high as 1 dBi.
关键词： multifunction antenna,ferromagnetic materials,multimode antenna,wideband antenna,Conformal antennas
更新于2025-09-23 15:19:57
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Compact and low insertion loss UWB ona??chip bandpass filter using coupled meandered line
摘要： For ultra-wideband (UWB) communication applications, a low-loss compact filter is proposed based on coupled lines using the GaAs integrated passive devices (IPD) technology in this letter. The multistage coupling lines are used to realize the ultra-wide passband with 100% fractional bandwidth. Two modified stubs loaded with shorted capacitors are introduced between coupled lines to produce a new transmission zero near the lower pass-band edge, resulting in better frequency selectivity performance. Moreover, stepped impedance resonator (SIR) structure is applied to the coupled lines to improve impedance matching performance within ultra-wide pass-band. As demonstrated, the proposed filter is fabricated as a chip with a compact size of 1.8 × 1.7 mm2, the insertion loss of the filter is less than 1.5 dB from 6 to 18 GHz with the return loss better than 13.5 dB. All simulated and measured frequency responses of the proposed filter are found to match well with each other, which further demonstrates the claimed superior performances of the proposed filter.
关键词： bandpass filter,coupled line,integrated passive devices technology,ultra-wideband
更新于2025-09-23 15:19:57
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3 Practical uses for topological photonics: An obscure phenomenon could improve chips, lasers, and quantum circuitry
摘要： A conformal permeable toroidal antenna operating in both a vertically polarized monopole mode and circularly polarized (CP) dipole mode in the UHF frequency range is designed based on theory of magneto-dielectric radiators. This antenna has been fabricated using a new advanced ferromagnetic laminate composite material whose high impedance and anisotropic properties enable an antenna that radiates via magnetic currents. The antenna, less than 0.5 m in diameter and less than 2 cm thick, was fabricated and tested. Including the imperfections of the feed network and a simple matching scheme, the antenna operates from 200 to 500 MHz with an input match of better than 10 dB, CP dipole realized gain as high as 2 dBi, and monopole mode vertically polarized gain as high as 1 dBi.
关键词： Conformal antennas,ferromagnetic materials,multimode antenna,multifunction antenna,wideband antenna
更新于2025-09-23 15:19:57