H-plane Half-power Beamwidth Research Articles

Triple-Mode Resonant Backfire Feed Antenna With Nearly Equal E-/H-Plane and Inverse Taper Patterns

A design approach to triple-mode resonant feed antenna is advanced for parabolic reflector antenna system. The antenna is composed of a slit-loaded 1.5-wavelength sectorial dipole, a primary corner reflector, and an auxiliary circular reflector. The corner angle of the primary reflector can be employed to properly narrow down the H-plane half-power beam width (HPBW), while with the E-plane one rarely affected, such that equal E-/H-plane characteristic can be yielded accordingly. Unlike traditional backfire antennas, high-order resonant modes are employed to generate inverse taper radiation pattern at the high frequency band. As is numerically demonstrated and experimentally validated, the corner angle of the primary reflector can be eventually determined as 45∘. The antenna exhibits an impedance bandwidth of up to about 79.7%, and a nearly equal E-/H-plane bandwidth of up to about 29.4%. Average HPBW of about 65∘, gain up to about 8.9 dBi with fluctuation of less than 1 dB can be achieved within the equal E-/H-plane bandwidth. The inverse taper radiation pattern at the high frequency band can provide effective edge illumination and uniform aperture field distribution in parabolic reflector antenna systems.

Novel corrugated rectangular dielectric resonator antenna with wide half power beam width

ABSTRACT In this work, a dielectric resonator antenna element is corrugated in a specific way, which led to increase its half power beam width (HPBW). The HPBW of the antenna is investigated for different values of corrugation depth and it has been concluded that HPBW can be increased by increasing this depth. By embedding periodic grooves in the DRA walls, it is possible to adjust the radiation intensity ratio of the upper wall to the side walls. By increasing this ratio, the HPBW of the antenna can be increased. To confirm the concept of beam widening method, a prototype of the corrugated DRA is fabricated and measured. Measured results show an impedance bandwidth of 23% (3.8–4.8 GHz). The measured E- and H-plane HPBWs at 4.1 GHz are 137° and 123°, respectively. Measured and simulated results are in a good agreement.

High Gain SIW H-Plane Horn Antenna with 3D Printed Parasitic E-Plane Horn

Substrate integrated waveguide (SIW) technology that combines 3D and 2D structures has been successfully utilized due to its notable advantages, including in its application to H-plane horn antennas. As this type of antenna is commonly constructed on thin substrates, the E-plane radiation pattern is always wide, thereby limiting the achievable gain performance. In this work, we propose an approach that incorporates 3D printed horns on a prefabricated SIW H-plane horn antenna to successfully narrow the E-plane radiation pattern, thereby improving the gain performance. The proposed E-plane horn is designed at the aperture of the original H-plane horn, providing a smooth and continuous wave transition from the thin substrate to the end-fire direction. This approach improves the directional radiation performance significantly and reduces fabrication time and associated difficulties as the parasitic structures are simply attached to the SIW horn, without the requirement of redesigning or refabricating the original antenna. From 20 to 25 GHz, an optimized prototype shows excellent performance. At 22.7 GHz, it exhibits 35° and 33° for the E- and H-plane half-power beamwidths (HPBWs), with corresponding side-lobe levels (SLLs) of −23 dB and −15 dB. The present research reveals that the proposed design presents high feasibility and a reduced demand for high-precision manufacturing processes at a lower cost, concomitantly providing an effective means to further improve on the radiation characteristics.

A Simple Linear-Type Negative Permittivity Metamaterials Substrate Microstrip Patch Antenna.

A microstrip patch antenna (MPA) loaded with linear-type negative permittivity metamaterials (NPMMs) is designed. The simple linear-type metamaterials have negative permittivity at 1–10 GHz. Four groups of antennas at different frequency bands are simulated in order to study the effect of linear-type NPMMs on MPA. The antennas working at 5.0 GHz are processed and measured. The measured results illustrate that the gain is enhanced by 2.12 dB, the H-plane half-power beam width (HPBW) is converged by 14°, and the effective area is increased by 62.5%. It can be concluded from the simulation and measurements that the linear-type metamaterials loaded on the substrate of MAP can suppress surface waves and increase forward radiation well.

The Design of Pixelated SIW Horn Antennas With Nearly Equal Beamwidths Using Binary Ink Stamp Optimization

In this paper, linearly and circularly polarized single-layer Substrate Integrated Waveguide (SIW) horn antennas with nearly equal half power beamwidths in principal planes for the 24 GHz ISM band are designed. The uniqueness of the solution lies in the application of a pixelated structure to the design of these SIW horn antennas. For the design, a novel heuristic algorithm called Binary Ink Stamp Optimization is proposed. At first, the ability of the proposed algorithm is proved over fifteen benchmark functions and compared with the results of six state-of-the-art optimization algorithms. Then, the novel algorithm is exploited for the design of the pixelated part of the antennas. The antennas are manufactured using low-cost 3D printing technology. The experimental results prove that the linearly polarized antenna has a reflection coefficient below −18 dB in the whole 24 GHz ISM band. At the center frequency of this band, the antenna gain is 14.2 dBi, and the level of side lobes is below −15 dB in E and H-planes. In addition, E and H-plane half power beamwidths are 26.5° and 25°, respectively. The circularly polarized antenna radiates a right-hand circularly polarized (RHCP) wave, the reflection coefficient, and axial ratio are below −12 dB and 3 dB in the whole 24 GHz ISM band, respectively. At the center frequency of this band, the antenna gain is 8.9 dBi and the level of side lobes is below −7.4 dB in both principal planes. Further, the half power beamwidths in principal planes are 30.6° and 33.4°, respectively.

Wideband Wide Beamwidth Full-Wavelength Sectorial Dipole Antenna Under Dual-Mode Resonance

In this article, a novel design approach to wide beamwidth dual-resonant, wideband sectorial dipole antennas is advanced. At first, a 1-D, full-wavelength dipole is evolved into a 2-D, sectorial dipole, so as to determine its two usable resonant modes. Then, both wideband and wide beamwidth characteristics are simultaneously attained under dual-mode resonance. Next, dual-resonant sectorial dipole antennas with flared angle of 270° and 240° are designed and studied. As experimentally validated, the proposed antenna exhibits an omnidirectional pattern with its impedance bandwidth over 70.4%. A few prototypes mounted above a ground plane are further investigated, so as to achieve a broad H-plane half-power beamwidth (HPBW) to over 120°. In addition, the antennas exhibit stable gain frequency response with fluctuation less than 2.2 dB within the entire impedance bandwidth. Thus, the advanced design approach based on 2-D dual-resonant, full- wavelength dipole leads to the formulation of novel wide beamwidth antennas with low frequency dispersion and simple configuration within a wide radiation bandwidth over 53.3%. Finally, a dual-polarized dipole antenna with port-to-port isolation higher than 34.5 dB and available radiation bandwidth of over 49% is implemented to further validate its potential for practical applications.

Wide beamwidth planar self‐balanced magnetic dipole antenna with enhanced front‐to‐back ratio

A design approach to a novel planar self-balanced, wide beamwidth magnetic dipole antenna with high front-to-back ratio (FBR) is advanced. The principle for FBR enhancement is revealed at first. As seen, the back-lobe level can be effectively suppressed by adjusting the unbalanced current ratio (UCR) factor: By varying the radius of the circular sector magnetic dipole antenna on the bottom layer and incorporating an arc-shaped branch at the end of the parasitic strip, the UCR factor can be properly tuned, and the back-lobe level can be flexibly controlled. Then, a set of closed-form formulas is derived to provide basic design guidelines and determine the initial value of key parameters. Parametric studies on FBR are then carried out to attain the ultimate designs in a step-by-step manner. As numerically and experimentally verified at the 2.45-GHz band, the FBR of a planar, air-substrate magnetic dipole antenna is indeed increased to over 30 dB with broadened E-/H-plane half-power beamwidth up to 130°/90°. Good agreement between the theoretical, numerical, and experimental results has evidently validated the proposed antenna design approach.

High‐gain antipodal Vivaldi antenna with metamaterial covers

A metamaterial slab covered antipodal Vivaldi antenna (MSAVA) is proposed to improve the radiation properties of the antipodal Vivaldi antenna (AVA). The metamaterial covers (MCs) consist of two types of metal rectangular ring arrays that have a higher effective permittivity than the substrate. The MCs can achieve a guiding effect and direct electromagnetic waves radiated from the side of AVA to the end-fire direction. The original AVA and the proposed MSAVA are simulated, fabricated and measured. The results show that of the two antennas is less than −10 dB in the frequency band of 0.95–11 GHz. Due to the introduction of MCs, MSAVA obtains a much narrower H-plane's half-power beamwidth, and the E-plane's is narrowed as well. The radiation gain is also improved in the frequency band. Moreover, the maximum gain of the proposed MSAVA is 17.67 dBi. Compared with the original AVA, the maximum gain is enhanced by 6.86 dB for the proposed MSAVA. The presented MSAVA featuring broad bandwidth, high gain and narrow beam has a high potential in ground penetrating radar, microwave imaging application and other broadband wireless systems.

Near‐constant beamwidth quadruple bandwidth double‐ridged horn antenna design

It is well known that the beamwidths of horn antennas are inversely proportional to frequency. Previous studies point to minimum ±12% beamwidth stability within a maximum of 2.5:1 bandwidth (BW) ratio. To extend this BW, a design methodology for broadband double-ridged horn antenna (DRHA) is proposed and applied to 4.5-18 GHz frequency band. Firstly, a conventional DRHA is designed and studied to compare the beamwidth variation of wideband horn antennas. By explicitly addressing the shortcomings of conventional DRHA, DRHA is redesigned and near-constant beamwidth DRHA is proposed using the modifications implemented on the sidewalls. The antenna utilises ridges to extend the frequency band, unlike other wideband constant beamwidth horns. The authors show that ridged horns, whose dimensions are appropriately designed and modified, can have stable beamwidths. Then, properly positioned curved pinwalls are designed to provide considerable improvement in H -plane beamwidth constancy. Broadband double-ridged waveguide-to-coaxial adapter is also designed for 50 Ω reference. The prototype is manufactured, and the measured antenna exhibits wideband characteristics with 30.9° ± 2.7° half power beamwidth in H -plane over 4:1 BW ratio. This variation corresponds to ±8.7% beamwidth stability along with the target frequency band.

A Magnetoelectric Dipole Antenna With Beamwidth Reconfiguration

This letter proposes a novel magnetoelectric (ME) dipole antenna with reconfigurable beamwidth characteristic in the E-plane, the H-plane, and both the E- and H-planes. In the proposed antenna, two pairs of tunable parasitic patches are placed in close proximity to the driven ME dipole. A varactor diode is inserted into each parasitic patch, and the mutual coupling between the parasitic patch and the ME dipole is tuned by adjusting the capacitances of the varactor diodes. The beamwidths of the proposed ME dipole antenna in the E-plane and the H-plane can not only be individually tuned but also be simultaneously changed. The designed ME dipole antenna has the tunable E-plane half-power beamwidth (HPBW) from 65° to 120°, the H-plane HPBW from 80° to 120°, and both the E-plane and H-plane HPBWs from 65° to 130° in a frequency band covering 2.0–2.1 GHz. A prototype was fabricated and measured. The good agreement between the measurement and the simulation validate the proposed design.

45–110 GHz Quad-Ridge Horn With Stable Gain and Symmetric Beam

A quad-ridge horn antenna with stabilized gain and minimum difference between E- and H-plane half-power beamwidths (HPBWs) is demonstrated for operation over 45–110 GHz bandwidth. Multistep flaring and corrugations on a finite ground plane are applied to obtain stable radiation patterns with 16-dBi minimum gain over the entire range. The computational studies are validated through measurements of a 3-D printed prototype using the direct metal laser sintering (DMLS) process. Accurate fabrication with achieved surface roughness of $ of the fabricated antenna is verified with digital microscope. The obtained gain variation, VSWR, and HPBW variation with rotation and over 45–110 GHz bandwidth are below 1.7 dB, 1.7:1, and 9°, respectively. This work demonstrates that the DMLS is a viable fabrication process for wideband horn antennas at millimeter-wave frequencies.

Wideband H‐plane dielectric horn antenna

By flaring a dielectric waveguide in the H-plane, an H-plane dielectric horn is formed, which could be directly excited by an SIW feed. However, matching and radiation performances are poor due to the thinness of the substrate. To improve these performances, some periodic parallel strips are printed both on the top and bottom planes of the dielectric horn. These strips guide and leak the electromagnetic waves gradually along the horn, finally enhancing the end-fire radiation both in H-plane and E-plane. Moreover, they increase the impedance bandwidth up to 38% in Ka-band, and improve the realised gain by around 2 dB. Indeed, a gain of 14.3 dBi is achieved at the centre frequency, with a front-to-back ratio of 27 dB, a side-lobe level of −22 dB in the H-plane, and the narrowed E-plane and H-plane half-power beamwidth of about 20°. The measured and simulated results agree with each other very well. In addition, the proposed H-plane horn antenna is very compact, low cost, and could be easily integrated.

Beamwidth Switchable Planar Microstrip Series-Fed Slot Array Using Reconfigurable Synthesized Transmission Lines

A planar microstrip series-fed slot antenna array, providing two-dimensional (2-D) beamwidth-switching capability, is presented and demonstrated. A newly developed reconfigurable synthesized line was incorporated into the feed network of the slot array as ON/OFF RF switches to enable the reconfigurability. With the aid of varactor diodes, the synthesized line can be switched between two states at the same frequency. In one state, it functions as a 50- $\Omega$ line for signal transmission, and in the other state, it is an open circuit for signal blockage. The switching is depended on the bias voltage, and the dc power consumption is very low. By wisely choosing the number of radiating elements, the E- and H-plane half-power beamwidths of the planar slot array can be shaped from (35°, 65°) to (15°, 31°). The broadside gain is varied from 7 to 14.5 dBi. The total efficiency remains better than 71%.

Low profile superstrate using transformation optics for semicircular radiation pattern of antenna

In this article, a dielectric superstrate inspired from transformation optics is presented. When placed over a patch antenna, this superstrate increases the half power beam width (HPBW) of a classical patch antenna. An appropriate spatial transformation relation with spatial compression and refractive index shift factors has been used to derive an expression for a dielectric material profile. The wave front exiting from the transformed space is optimized for a semicylindrical shape. Then, a discretized version of this profile has been used to design a cuboidal superstrate. Full wave simulations have been presented that essentially show a superstrate device capable of producing a 297° of HPBW in H-plane with a peak directivity of 3.2 dBi at the design frequency. The derived solution can be realized using the standard dielectric materials for real-world applications.

Design and Research on a 24GHz Microstrip Array Antenna

A 24 GHz microstrip array antenna based on series and parallel combination feeding network is designed in this paper by theoretical and experimental study. The whole design process includes theoretical analysis, HFSS ( High Frequency Structure Simulator ) simulation and practical manufacture. The array antenna design mainly includes four parts, design of the microstrip patch element, determining the number of radiating patch elements, determining the distance between every two adjacent patch elements and design of feeding network. Then, the microstrip array antenna is simulated and optimized by HFSS. The simulation results show that the VSWR ( Voltage Standing Wave Ratio ) characteristics present good, the maximum gain reaches 21dB and E-plane together with H-plane half-power beamwidth is as small as about 11.8 o . Both of the first side lobe levels are about-14 dB reaching the design requirements. After practical manufacture, the testing results show that the various indicators coincide with the simulation results and the antenna is reliable with stable performance.

Beam shaping of waveguide radiators

The far-field radiations from corner-cut waveguide with obstacle in the aperture have been investigated in the two principal planes. Besides the effect of the wire obstacle, the angular symmetrical cuts in the waveguide corners control the H-plane beamwidth without any substantial change in E-plane. Radiation pattern measurements are shown for a number of angular cuts, α, and a parameter K. The H-plane half power beam width is broadest for 40° < α < 500° corner-cut and K equal to 0.5