Browsing by Author "Ng, Herman Jalli"

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Beam Squinting in Wideband 60 GHz On-Board Series-Fed Differential Patch Arrays
(2017-01-01)
Ahmad, Wael A.
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Lu, Jeng-Hau
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Kissinger, Dietmar
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Ng, Herman Jalli
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電信工程研究所
This paper examines the beam squinting phenomenon in millimeter-wave wideband series-fed on-board arrays with respect to the number of elements and bandwidth as an inherent scanning capability. 4-element and 6-element wideband 60 GHz differential patch arrays are designed, fabricated and measured. Both arrays cover more than 6 GHz of impedance bandwidth. The 6-element array undergoes 22 degrees beam squinting over 8 GHz with 13 dBi average gain, while the 4-element array undergoes 15 degrees squinting over 6 GHz with 11 dBi average gain.
Design and Characterization of a Differential Microstrip Patch Antenna Array at 122 GHz
(2018-01-01)
Hasan, Raqibul
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Ahmad, Wael A.
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Lu, Jeng-Hau
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Kissinger, Dietmar
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Ng, Herman Jalli
This paper presents a differential microstrip patch antenna array that operates at 122 GHz and is suitable for radar applications. The differential line was chosen in the proposed antenna due to the differential radar transceiver. The microstrip patch antenna array was designed to achieve a higher gain and bandwidth compared to a single element antenna. An 8-element series-fed array was designed, fabricated and measured. The 8-element array provides an impedance bandwidth of 14 GHz and a gain of around 13.74dBi at 122 GHz. These measurement results are also in good agreement with the simulation results.
Design and Characterization of Series and Corporate Feed Differential Arrays for Broadband 60 GHz Radar Applications
(2017-01-01)
Ahmad, Wael Abdullah
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Lu, Jeng-Hau
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Hasan, Raqibul
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Kissinger, Dietmar
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Ng, Herman Jalli
This paper provides a comparison between differential broadband series-fed and corporate-fed 4-element arrays at 60 GHz band to equip multi-channel radar. Radiator lengths are perturbed in the series-fed array to widen the bandwidth, while parasitic structures are inserted in the corporate-fed array. Measurement showed beam squinting from 3 degrees to 15 degrees over 61-66 GHz and narrow beam width for the compact series-fed array, while the large corporate-fed array has fixed beam direction but wider beam width. This opens the possibility of inherent beam steering by series-fed arrays for radar applications.
Design of a Novel Microstrip Franklin Leaky-Wave Antenna Using the Eigenstate Approach
(2019-07-01)
Lu, Jeng-Hau
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Ng, Herman Jalli
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Kissinger, Dietmar
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Jou, Christina F.
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Wu, Lin-Kun
This paper presents the design of a novel periodic leaky-wave antenna (LWA) using modified microstrip Franklin unit cells. Two additional quarter-wave couple-line sections are used to allow the cell to work with the n = -2 fast-wave harmonic. It allows the use of low-epsilon(r) substrates so the designed LWA is cost-effective, can be easily integrated with radar front-end circuits, and avoids the excitation of surface waves. A novel application of eigenstate analysis leads to a simpler and more intuitive approach for the implementation of the reflection cancellation concept to eliminate open-stopband (OSB) effects. This is realized in the proposed structure with the use of a pair of interdigital fingers and different widths for the two lines forming the coupled section. A general design flow is also proposed for the design of the unit cell and LWA. Finally, a 40 cell LWA is fabricated on a Rogers 3003 substrate with epsilon(r) = 3. The measured results show that the beam scans continuously from -54 degrees to +55 degrees when frequency is varied from 54.7 to 70 GHz, and no visible OSB effect is observed near the broadside direction.
F-Band Differential Microstrip Patch Antenna Array and Waveguide to Differential Microstrip Line Transition for FMCW Radar Sensor
(2019-08-01)
Hasan, Raqibul
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Ahmad, Wael Abdullah
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Lu, Jeng-Hau
;
Ng, Herman Jalli
;
Kissinger, Dietmar
This paper describes a differential microstrip patch antenna array and a rectangular waveguide to coupled differential microstrip line transition operating at 122 GHz. The antenna array is realized in series-fed topology/architecture and is very suitable for MIMO radar applications. This on-board antenna provides a high antenna gain and radiation efficiency at millimeter-wave frequencies. The rectangular waveguide transition with low insertion loss offers the facilities to characterize the on-board antenna and can also be utilized in a radar system in combination with a horn antenna. The measured bandwidth of the antenna array is 7 GHz with a maximum gain of 12.98 dBi at 122 GHz. The waveguide transition has a bandwidth of 20 GHz at 10-dB return loss. Radar measurements were performed using radar sensors that were equipped with the developed antenna array as well as the waveguide transition in combination with horn antenna for comparison purposes. The radar measurement results with on-board antenna array show a good performance for detecting the range of the target.
Highly-Miniaturized 2-Channel mm-Wave Radar Sensor with On-Chip Folded Dipole Antennas
(2017-01-01)
Ng, Herman Jalli
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Ahmad, Wael
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Kucharski, Maciej
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Lu, Jeng-Hau
;
Kissinger, Dietmar
This paper describes a miniaturized 2-channel system-on-chip radar sensor in a SiGe BiCMOS technology. It includes on-chip folded dipole antennas that utilize a localized backside etching technique with a novel selective etching approach that is able to improve the radiation efficiency and the mechanical stability of the chip. The transceiver is equipped with a 30-GHz VCO that is complemented with a frequency quadrupler to generate a 120-GHz carrier signal. The 2 transmit channels can be combined to increase the effective isotropic radiated power by 6 dB and to implement a SIMO radar. The transceiver also includes BPSK modulators as well as I/Q receivers and can be utilized to build a flexible MIMO radar using frequency-modulated continuous-wave with time and delta-sigma modulator-based frequency division multiplexing as well as pseudo-random noise radar techniques. Radar measurement using digital-beamforming method with 10-GHz modulation bandwidth was performed to show the applicabilty of the proposed system.