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A compact, single-layer, wideband, tilted-beam microstrip antenna with customized tilt angle is presented. The antenna is comprised by one subwavelength driven patch and several subwavelength parasitic patches. The tilt angle of t...
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A compact, single-layer, wideband, tilted-beam microstrip antenna with customized tilt angle is presented. The antenna is comprised by one subwavelength driven patch and several subwavelength parasitic patches. The tilt angle of the antenna is determined by the index distributions of those subwavelength patches. The detailed index-modulation principle is developed from the generalized law of refraction, wherein the reflection phase is mapped to the index by utilizing the equivalent transmission-line theory and the transverse resonance technique. As a result, the tilt angle could be customized by allocating patch cells following specific index distributions. On top of that, as a new degree of freedom in design, one could choose subwavelength patches with low dispersion characteristics as unit cells to further enhance the operational bandwidth and improve the stability of radiation pattern. For demonstration, two types of I-shaped patch units with different dispersion characteristics have been utilized to configure tilted-beam antennas that follow the same index distributions. In addition, the effectiveness of the developed tilted-beam antenna for array application has been proven. Experiments have been carried out to verify their performance.
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The design method of a dual-polarized array antenna is investigated and presented in this communication. The antenna consists of a series-fed patch array (SFPA) antenna for vertically polarized (VP) radiation and a slotted microst...
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The design method of a dual-polarized array antenna is investigated and presented in this communication. The antenna consists of a series-fed patch array (SFPA) antenna for vertically polarized (VP) radiation and a slotted microstrip first higher order mode (EH1-mode) periodic leaky-wave antenna (P-LWA) for horizontally polarized (HP) radiation. These two antennas are both analyzed by using the leaky-wave antenna method. It is revealed that the SFPA/EH1-mode element is expected to be operated under the short-/open-circuited condition, at which the desired VP/HP broadside radiation can be realized. Afterward, by reusing the radiator of the EH1-mode element as the ground of the SFPA one, the radiation apertures of these two elements can be designed in an overlapped style. Finally, a dual-polarized array antenna operated at 24.0 GHz is fabricated and tested for verification. The measurements demonstrate and validate that both the desired high-gain VP and HP radiation patters are achieved at broadside.
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This article presents, for the first time, a balloon-based conformal array antenna for emergency communication applications in low-range hilly forest scenarios. Fed by a simple, flexible phase shifting network, the antenna feature...
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This article presents, for the first time, a balloon-based conformal array antenna for emergency communication applications in low-range hilly forest scenarios. Fed by a simple, flexible phase shifting network, the antenna features broadened bandwidth, high gain, and steerable directional beam, outperforming other electrically thin conformal array antennas in terms of comprehensive performance. The basic array element is a cylindrically conformal microstrip patch antenna, whose bandwidth is widened by adding parasitic patches loaded by shorting pins for size miniaturization and mutual coupling reduction. Then, a
$1 \times 4$
conformal subarray with parallel feeding network is designed and optimized for beam sharpening in the elevation plane. To further increase the gain and enable beam steering for full azimuthal coverage, the balloon is surrounded by multiple
$1 \times 4$
conformal subarrays, and only four of them operate at a time. A flexible phase shifting network is designed for beam steering along the azimuthal direction. To validate the effectiveness of the designs, a prototype was fabricated and measured. Experimental results show the antenna exhibits a gain of around 15 dB and a bandwidth of 74 MHz at the 2.4 GHz band, which has demonstrated the good performance of the balloon conformal array antenna and its huge potential in low-range hilly forest communication applications.
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This article presents a new design and experimental verification of a broadband wide-beam microstrip array antenna for short-range automotive radar sensors. The antenna is designed based on a pure microstrip transmission line, by ...
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This article presents a new design and experimental verification of a broadband wide-beam microstrip array antenna for short-range automotive radar sensors. The antenna is designed based on a pure microstrip transmission line, by inserting short inverted trapezoidal stubs alternately on both sides of the microstrip line periodically to generate a trapezoid-cascaded electric field, which enables the proposed antenna to radiate effectively. Therefore, the proposed antenna has the advantage of a simple structure. The antenna has a larger effective radiation aperture, which leads to a smaller quality factor, so the antenna has a broad bandwidth of 13% (74.02–85.08 GHz), completely covering 76–81 GHz automotive radar frequency band. The peak gain is up to 10.4 dBi. Based on the proposed antenna, a three transmitting antennas and four receiving antennas (3T4R) multiple-input-multiple-output (MIMO) radar antenna array is designed. To reduce the influence of strong surface waves on the radiation pattern, a design conception of a dummy array with an absorbing load is introduced. The array antenna of each transmitting (TX)/receiving (RX) channel can achieve a wide half-power beamwidth (HPBW) of 120° in the azimuth plane. Besides, the MIMO array exhibits good consistency, with the absolute amplitude error of TX-RX channels less than 3 dB and the phase error less than 20° in the azimuth plane.
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A compact series-fed, omnidirectional printed dipole array for millimeter-wave (mm-wave) bands n257, n259, and n261 is proposed. A series feed technique with microstrip to grounded-co-planar waveguide (CPW) transition was used to ...
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A compact series-fed, omnidirectional printed dipole array for millimeter-wave (mm-wave) bands n257, n259, and n261 is proposed. A series feed technique with microstrip to grounded-co-planar waveguide (CPW) transition was used to feed the antenna. The prototype was fabricated and measured for the range from 27.25 to 28.5 GHz. The measured peak gain is 10.3 dBi with a maximum azimuthal ripple of 4.4 dB.
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This paper presents a new method of designing and implementing low-cost series-fed microstrip antenna arrays with low sidelobe levels by applying standard single-layer PCB technology. The method is based on the Z-parameter charact...
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This paper presents a new method of designing and implementing low-cost series-fed microstrip antenna arrays with low sidelobe levels by applying standard single-layer PCB technology. The method is based on the Z-parameter characteristics obtained from the electromagnetic full-wave simulation of the array elements by using a two-port network model. Two types of antenna arrays are designed and presented with the use of the proposed method. The first type is a uniform linear array with sidelobe level of 24.2 dB at the 24.125 GHz frequency band. The second type is a nonuniform linear array that provides at least 50\% more physical space between the central patches to be used in 2-D arrays; this antenna has sidelobe level of 25 dB at 24.125 GHz. Both antennas achieve an excellent performance in the entire bandwidth of 250 MHz.
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In this paper, a full solid angle scanning cylindrical- and-conical (CYLCON) conformal phased array antenna (PAA) is designed. First, a microstrip Yagi antenna with low profile and small size is proposed and discussed. Second, a c...
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In this paper, a full solid angle scanning cylindrical- and-conical (CYLCON) conformal phased array antenna (PAA) is designed. First, a microstrip Yagi antenna with low profile and small size is proposed and discussed. Second, a cylindrical conformal Yagi antenna array consisting of 24 aforementioned 8-element Yagi antennas is designed and optimized. Simulation results show that the Yagi antenna array can realize low-elevation beam scanning in the region of 0° ≤ θ ≤ 30°, 30° ≤ φ ≤ 150° with low sidelobe levels and sharp beams. Third, CYLCON conformal microstrip antenna arrays are developed to realize the broadside beam scanning. Afterwards, an integrated PAA by combining the aforementioned conformal arrays along with feeding networks is constructed to achieve full solid angle scanning. Finally, a prototype is fabricated, the measured results show that it can realize beam scanning in the regions of 0° ≤ θ ≤30°, 30° ≤ φ ≤ 150°, and 30° ≤ θ ≤ 180°, 60° ≤ φ ≤ 120°, which meet well with those of the simulated. By arranging proper number of arrays along the perimeter accompanied with the switchable feeding configurations, a full solid angle scanning can be achieved.
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Road safety applications drive the development of vehicular communications as support to intelligent transport systems. The communications network necessary for this is supported by dedicated short-range communications (DSRC), whi...
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Road safety applications drive the development of vehicular communications as support to intelligent transport systems. The communications network necessary for this is supported by dedicated short-range communications (DSRC), which is based on roadside units (RSUs) and onboard units. In the RSU, the DSRC physical-layer standards, along with practical issues, require specific radiation patterns of the respective antenna, leading to the use of unusual arrays of antennas. This paper describes a new concept based on a binomial array structure, which simplifies the design of the antenna array while ensuring good performance. The new structure developed for this antenna enabled the design of a feed network using unbalanced power dividers in the same plane as that of the radiating elements, maintaining the favorable characteristics of microstrip antennas. The array thus obtained met the desired specification, in terms of a radiation pattern with a bandwidth greater than 1 GHz.
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In [1], the authors refer to the described antenna as "new," and state that they have applied for a patent to protect their rights. In fact, the described antenna is a special case of my patent [2], which expired many years ago. F...
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In [1], the authors refer to the described antenna as "new," and state that they have applied for a patent to protect their rights. In fact, the described antenna is a special case of my patent [2], which expired many years ago. Fig. 1 of my patent describes a collinear array of radiator elements composed of sections of microstrip outer (ground) conductors. An inner conductor progressively feeds each radiator element at its ends. This is accomplished by abrupt changes in both inner and outer conductor widths at half-wavelength intervals in the microstrip. Each change in width effectively transposes microstrip inner and outer conductors. This connection of inner-to-outer conductor sets up a potential difference between adjacent radiator ends, which excites the radiators. Transposition also renders each radiator element cophasal at the operating frequency by providing the requisite 180 deg phase change that compensates for the propagation delay on feeding each radiator at the operating frequency.
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In this paper, a broadband 20 × 20 microstrip antenna array is presented. Once a rectangular microstrip patch antenna with parasitic patches as an element antenna has been optimized at 24.2-26.7 GHz, a parallel-series feed networ...
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In this paper, a broadband 20 × 20 microstrip antenna array is presented. Once a rectangular microstrip patch antenna with parasitic patches as an element antenna has been optimized at 24.2-26.7 GHz, a parallel-series feed network with minimum feed lengths can be utilized to combine element antennas. From simulation and measurement, the array antenna yields relatively high gains of 26.0-30 dB and narrow 3 dB beamwidths (44.5-5.1° in the H-plane and 41-71° in the E-plane, respectively in an LMDS band.
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