A bidirectional quasi-endfire patch antenna with a low elevation angle has promising applications for wireless communication systems that are vehicle-based, airborne, and shipborne. In this paper, the shortened patch resonators and open patch resonator are integrated to form a bidirectional quasi-endfire patch antenna with low elevation angle. The open patch resonator operates with a TM mode to realize bidirectional radiation. The two shortened patch resonators operate with a TM mode coupled with a TM mode to control the phase difference between them at a suitable angle, so that the shortened patch resonators act as directors to tilt the dual beams toward the endfire direction and achieve low elevation angle. Compared with reported patch antennas with dual beams, the proposed antenna has the lowest elevation angle and a compact structure. For demonstration purposes, an antenna prototype operating at 3.5 GHz is fabricated and measured, exhibiting a low elevation angle of ±28°, a -10 dB impedance matching bandwidth from 3.44 GHz to 3.61 GHz, and a size of 1.36 λ × 0.57 λ with a profile of 0.036 λ. A prototype with two pair of shortened patch directors further reduces the elevation angle to ±19° with the size of 2.3 λ × 0.57 λ.
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http://dx.doi.org/10.3390/mi15060777 | DOI Listing |
Int Ophthalmol
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Department of Ophthalmology and Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, 83 Fenyang Road, Shanghai, 200031, China.
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Maritime Engineering Research Group, School of Engineering, University of Southampton, SO16 7QF UK.
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Chemistry Discipline, Khulna University, Khulna 9208, Bangladesh.
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Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, USA; North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, USA. Electronic address:
Elevated intraocular pressure (IOP) is implicated in the structural and functional damage to the retinal ganglion cells (RGCs) in primary open-angle glaucoma (POAG). Topical IOP lowering agents provide short-term relief, necessitating frequent dosing. Moreover, non-adherence to frequent eyedrops administration contributes significantly to visual field loss and worsens the disease outcome.
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Western University Schulich School of Medicine and Dentistry, London, Ontario, Canada.
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