The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Xianming Qing - One of the best experts on this subject based on the ideXlab platform.
-
270 ghz ltcc integrated high gain cavity backed fresnel zone plate lens antenna
IEEE Transactions on Antennas and Propagation, 2013Co-Authors: Zhi Ning Chen, Xianming QingAbstract:A compact cavity-backed Fresnel zone plate (FZP) lens antenna, integrated in low-temperature co-fired ceramic (LTCC) is proposed to achieve high gain at 270 GHz band. The gain is enhanced by using the back cavity formed by a via sidewall and a ground plane. A compact feeding transition is proposed to realize the broadband impedance matching in order to reduce the considerably large reflection at high permittivity substrate-air interface when the antenna is directly fed by an external air-filled waveguide. The measured results show that the proposed cavity-backed FZP lens antenna achieves a boresight gain of 20.8 dBi at 270 GHz and a 3-dB gain bandwidth of 9.1 GHz (266.2–275.3 GHz).
-
multilayered composite right left handed leaky wave antenna with consistent gain
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Zhi Ning Chen, Xianming QingAbstract:A multilayered composite right/left-handed (CRLH) based leaky-wave antenna is proposed for the continuous beam scanning from backward to forward direction with consistent gain. The antenna comprises a substrate integrated waveguide (SIW) with an array of the CRLH unit cells. The CRLH unit cell is formed by a slot cut on the upper ground of the SIW, and a parasitic patch beneath the slot. The antenna achieves continuous beam scanning against frequency and the optimal boresight gain at the balanced condition frequency. The antenna prototype with 15 unit cells exhibits the measured beam scanning angle of -66° to 78° over the frequency range from 8.0 to 13.0 GHz with a consistent gain of more than 9.0 dBi.
Zhi Ning Chen - One of the best experts on this subject based on the ideXlab platform.
-
270 ghz ltcc integrated high gain cavity backed fresnel zone plate lens antenna
IEEE Transactions on Antennas and Propagation, 2013Co-Authors: Zhi Ning Chen, Xianming QingAbstract:A compact cavity-backed Fresnel zone plate (FZP) lens antenna, integrated in low-temperature co-fired ceramic (LTCC) is proposed to achieve high gain at 270 GHz band. The gain is enhanced by using the back cavity formed by a via sidewall and a ground plane. A compact feeding transition is proposed to realize the broadband impedance matching in order to reduce the considerably large reflection at high permittivity substrate-air interface when the antenna is directly fed by an external air-filled waveguide. The measured results show that the proposed cavity-backed FZP lens antenna achieves a boresight gain of 20.8 dBi at 270 GHz and a 3-dB gain bandwidth of 9.1 GHz (266.2–275.3 GHz).
-
multilayered composite right left handed leaky wave antenna with consistent gain
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Zhi Ning Chen, Xianming QingAbstract:A multilayered composite right/left-handed (CRLH) based leaky-wave antenna is proposed for the continuous beam scanning from backward to forward direction with consistent gain. The antenna comprises a substrate integrated waveguide (SIW) with an array of the CRLH unit cells. The CRLH unit cell is formed by a slot cut on the upper ground of the SIW, and a parasitic patch beneath the slot. The antenna achieves continuous beam scanning against frequency and the optimal boresight gain at the balanced condition frequency. The antenna prototype with 15 unit cells exhibits the measured beam scanning angle of -66° to 78° over the frequency range from 8.0 to 13.0 GHz with a consistent gain of more than 9.0 dBi.
P C Stek - One of the best experts on this subject based on the ideXlab platform.
-
C.: Design and field-of-view calibration of 114–660 GHz optics of the Earth Observing System Microwave Limb Sounder
2016Co-Authors: R E Cofield, P C StekAbstract:Abstract—This paper describes the optics design and field-of-view (FOV) calibration for five radiometers covering 114–660 GHz which share a common antenna in the Microwave Limb Sounder instrument on the National Aeronautics and Space Administra-tion’s Aura satellite. Details of near-field pattern measurements are presented. Estimated systematic scaling uncertainties (3) on cal-ibrated limb emissions, due to FOV calibration uncertainties, are below 0.4%. 3 uncertainties in beamwidth and relative pointing of radiometer Boresights are 0.006 and 0.003, respectively. The uncertainty in modeled instrument response, due to the scan de-pendence of FOV patterns, is less than 0 24K equivalent black-body temperature. Refinements to the calibration using in-flight data are presented. Index Terms—Calibration, microwave optics, near-field range, remote sensing
-
design and field of view calibration of 114 660 ghz optics of the earth observing system microwave limb sounder
IEEE Transactions on Geoscience and Remote Sensing, 2006Co-Authors: R E Cofield, P C StekAbstract:This paper describes the optics design and field-of-view (FOV) calibration for five radiometers covering 114-660 GHz which share a common antenna in the Microwave Limb Sounder instrument on the National Aeronautics and Space Administration's Aura satellite. Details of near-field pattern measurements are presented. Estimated systematic scaling uncertainties (3/spl sigma/) on calibrated limb emissions, due to FOV calibration uncertainties, are below 0.4%. 3/spl sigma/ uncertainties in beamwidth and relative pointing of radiometer Boresights are 0.006/spl deg/ and 0.003/spl deg/, respectively. The uncertainty in modeled instrument response, due to the scan dependence of FOV patterns, is less than /spl plusmn/0.24 K equivalent black-body temperature. Refinements to the calibration using in-flight data are presented.
Karu P Esselle - One of the best experts on this subject based on the ideXlab platform.
-
a novel boresight and conical pattern reconfigurable antenna with the diversity of 360 polarization scanning
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Yang Yang, Roy B V B Simorangkir, Xi Zhu, Karu P Esselle, Quan XueAbstract:A novel design of boresight and conical pattern reconfigurable antenna with the capability of 360° polarization scanning is presented in this paper. At boresight mode, the antenna produces a continuously reconfigurable polarization over 360° in the azimuth plane, which provides adaptive-polarization reception between a transmitter and a receiver. The antenna is analyzed in terms of the electric field with an explanation of the generation of TM11 and TM02 resonant modes, which provides an innovative method of designing pattern reconfigurable antennas for the WLAN applications. The proposed method is validated by a good agreement between simulation and experimental results for an antenna designed to provide boresight and conical pattern switching at 2.4 GHz. The gain of 6.05 dBi and efficiency of 86.7% are measured in the boresight mode, corresponding to 4.39 dBi and 82.4% at conical mode.
-
a low profile compact microwave antenna with high gain and wide bandwidth
IEEE Transactions on Antennas and Propagation, 2007Co-Authors: Karu P EsselleAbstract:We demonstrate a low-profile, compact antenna consisting of a cross dielectric resonator on a microstrip patch and a quasi-planar surface mounted short horn (SMSH). The measurements show a 10 dB return loss bandwidth from 6.07 GHz to 7.52 GHz (21.3%) and a gain better than 9.0 dBi over this bandwidth. The total height of the antenna is only 8.61 mm and the aperture size is 48.1 mm X 43.1 mm. The cross-polarization level of the antenna at boresight is better than 28 dB in both E-and H-planes over the impedance bandwidth.
S W Cheung - One of the best experts on this subject based on the ideXlab platform.
-
a low profile dual polarized patch antenna with stable radiation pattern using ground slot groups and metallic ground wall
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: S W Cheung, Changfei ZhouAbstract:A low-profile dual-polarized patch antenna with stable radiation pattern for use in base stations operating from 1.7 to 2.7 GHz is presented. The antenna consists of a square patch radiator placed at 20 mm ( $0.14\lambda _{0}$ at the center frequency of 2.2 GHz) above a square ground plane. For bandwidth enhancement, the square patch radiator is dual fed using four probes, each having a U-shape. Two wideband 180° baluns are designed using composite right/left handed transmission lines to generate two signals with same amplitude, but phase shift of 180° for the probes. The radiation pattern is stabilized using four slot groups on the ground plane and a metallic ground wall around the radiating patch. The antenna is studied and designed using computer simulation. Results show that the simulated half-power beamwidths have variations of only 4° and 5° in the elevation (EL) and azimuth (AZ) planes, respectively, across the operating band. Measured results show that the antenna has the impedance bandwidths of 1.68–2.83 GHz and 1.7–2.85 GHz for the two input ports, isolation of more than 38 dB, and cross-polarization of less than −20 dB at the boresight in both the EL and AZ planes. The measured boresight gains are 7.8 ± 0.6 dBi for both two ports, and the radiation efficiencies are 74%–84% and 73%–82% for ports 1 and 2, respectively.
-
design of polarization reconfigurable antenna using metasurface
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: H L Zhu, S W Cheung, X H Liu, T I YukAbstract:A planar polarization-reconfigurable metasurfaced antenna (PRMS) designed using metasurface (MS) is proposed. The PRMS antenna consists of a planar MS placed atop of and in direct contact with a planar slot antenna, both having a circular shape with a diameter of 78 mm (0.9 $\lambda_{0}$ ), making it compact and low profile. By rotating the MS around the center with respect to the slot antenna, the PRMS antenna can be reconfigured to linear polarization, left-hand and right-hand circular polarizations. An equivalent circuit is used to explain the reconfigurability of the antenna. The PRMS antenna is studied and designed to operate at around 3.5 GHz using computer simulation. For verification of simulation results, the PRMS antenna is fabricated and measured. The antenna performance, in terms of polarization reconfigurability, axial-ratio bandwidth, impedance bandwidth, realized boresight gain and radiation pattern, is presented. Results show that the PRMS antenna in circular polarizations achieves an operating bandwidth of 3.3–3.7 GHz (i.e., fractional bandwidth 11.4%), a boresight gain of above 5 dBi and high-polarization isolation of larger than 15 dB. While the PRMS antenna in linear polarization achieves a gain of above 7.5 dBi with cross-polarization isolation larger than 50 dB.