Substrate Integrated Waveguide Horn Antenna Research Articles

High-gain H-plane SIW horn antenna loaded with dielectric slab for ku band low RCS applications

This article presents the design, simulation and experimental measurements of an H-Plane substrate-integrated waveguide (SIW) Horn Antenna Loaded with FR-4 Slab for Low RCS (radar cross section) applications like defence sector at Ku band (12-16 GHz). The design facilitates high gain and good impedance bandwidth (IBW). Also, the proposed structure has simple feed, planar structure with low-cost FR-4 substrate as dielectric material and decomposed into two parts. The former part of the antenna is the feeding part, which consists of two metallic plates filled with air substrate and a 90-degree corner reflector designed by shortening the metallic plates. The later part of the antenna is loaded with the FR-4 substrate that enhance the peak gain of the structure significantly. A simple coaxial probe is employed for the excitation of the corner reflector antenna. After the design is conferred by simulations, the same is fabricated and the performance measured experimentally. The experimental results are in close agreement with the simulated results. The design has yielded a 10 dB bandwidth of 30% (11.6–16 GHz), and a stable endfire radiation pattern over the entire bandwidth with a peak gain of 18.5 dBi at 14 GHz. Also, the design has F/B ratio > 20 dB over entire 10 dB bandwidth. Moreover, the antenna produced low RCS < 20 dB(m2) from −30° to +180° of elevation angle. Therefore antenna can’t easily detected from the radar system and suitable for defence applications.

Low-Profile Dual-Polarized Antenna Integrated with Horn and Vivaldi Antenna in Millimeter-Wave Band

In this paper, a dual-polarized antenna based on a substrate-integrated waveguide (SIW) horn antenna and Vivaldi antenna is proposed. The horizontal polarization (HP) is achieved by using the H-plane SIW horn antenna, while the vertical polarization (VP) is realized by a typical Vivaldi antenna etched on the surface of the SIW horn antenna. In front of the horn aperture, a dielectric lens is designed to optimize impedance matching and enhance directivity. Different feeding structures of the two polarizations are used to enhance the isolation between the two ports. The measured results demonstrate a 20.04–25.5 GHz (23.97%) overlapped dual-polarized impedance bandwidth, and the measured maximum gains of the HP and VP are 5.2 dBi and 8.2 dBi, respectively. A good isolation of 35 dB within the operating band is realized. The proposed dual-polarized antenna meets the demand to transmit and receive signals in two polarization directions simultaneously for wireless communication well.

H-plane SIW horn antenna with enhanced front-to-back ratio for 5G applications

Millimeter-wave (mmWave) antennas are indispensable components in the fifth-generation (5G) wireless communication systems. With the inherent advantages of integration capability, substrate integrated waveguide (SIW) antenna is an excellent choice for applications in the mmWave frequency bands. However, reflection losses occur at dielectric-filled thin apertures of SIW antennas. These reflections can be overcome by impedance matching between the aperture and the free space. In this study, we introduce an mmWave SIW horn antenna having impedance matching transitions (IMTs) across the horn's aperture width. The designed antenna, operating in the 24-28 GHz band, is simulated with a full-wave analysis tool. The simulation results of the modified SIW horn have been confirmed by the experimental results and shown to be satisfactory. The IMTs result in an enhancement of the front-to-back ratio (FTBR). The modified SIW horn antenna with a novel printed transition achieves sidelobe levels (SLLs) of better than ?9 dB at 27 GHz, with an enhanced FTBR above 15 dB. In the 24?28 GHz band, the antenna has a reflection coefficient variation of better than ?10 dB.

Wideband high gain SIW horn antenna loaded with half Maxwell fish‐eye fabricated by 3‐D‐printing

AbstractThis letter presents a wideband high gain substrate integrated waveguide horn antenna (SIWHA) loaded with half Maxwell fish‐eye (HMFE) fabricated by 3‐D‐Printing. The impedance bandwidth of the SIWHA is narrow, mainly caused by the discontinuity between the substrate with the air. By introducing the HMFE and a match layer between the SIWHA with HMFE, the impedance continuity can be realized, which can not only improve the impedance bandwidth but also enhance the antenna gain. Experimental results show that the proposed antenna can achieve more than 6 dBi gain and 60.9% relative impedance bandwidth with reflection coefficients lower than −10 dB.

Holey SIW Horn Antenna Based on an H-Plane Lenswise Wavefront Collimation

This communication presents an H-plane substrate integrated waveguide (SIW) horn antenna whose directivity is enhanced using holey unit cells along the horn flaring. By wisely drilling the horn antenna, it is possible to reduce the phase error in the aperture which is a common problem in horn antennas if the optimum dimensions are not used. An analysis of the distribution of the unit cells along the horn antenna has been carried out to achieve the desired equivalent refractive indices. By changing the hole radius, different equivalent refractive indices can be tuned with a wideband performance. This fact enables the implementation of a collimation zone inside the horn antenna which transforms the pseudocircular wavefront into a quasi-planar one in the radiating aperture. The produced directivity is similar to the horn antenna with the optimum dimensions, but a longitudinal reduction of 53.7% and a higher realized gain are achieved. A holey SIW horn antenna is designed and manufactured. The measured results show an impedance bandwidth performance below −10 dB from 34.3 to 44.5 GHz (25.9%) with a realized gain above 10 dBi. The gain difference regarding an SIW horn antenna without the collimation zone is about 2–3 dBi in the operating frequency range.

Design of planar wideband surface‐wave excited substrate integrated waveguide horn antenna loaded with metamaterials

AbstractIn this paper, a wideband planar substrate integrated waveguide (SIW) horn antenna based on surface wave excitation through loading metamaterials is designed. Strong coupling effect is realized between the employed bilayer metamaterial unit with the top layer as a π‐shaped‐slotted patch while the bottom layer as the complementary cross‐shaped‐slotted patch. The equivalent permittivity of the extended substrate in front of the planar horn aperture can be effectively reduced to unity and impedance mismatching for conventional planar SIW horn antenna can be reduced in a wide bandwidth. Results indicate that the working frequency of the antenna is 12.3–15.8 GHz with the relative impedance bandwidth of 24.6%.

Gain enhancement of a SIW H-plane horn antenna using of metamaterial array

Abstract In this paper, a novel, compact and high gain H-plane horn antenna with Substrate Integrated Waveguide (SIW) technology is examined for X-band applications. To increase the gain, an array of metamaterials is used by cutting the gap in the aperture area of the antenna in high metallization. After examining the size and position of the metamaterial unit cell and several array elements, which act as a focusing structure, and in addition, by reducing the electric permittivity coefficient of the substrate and consequently reducing the losses, an increase in gain is achieved. The performance of the proposed SIW horn antenna with metamaterials has been compared with the SIW conventional horn antenna without metamaterials. To highlight this point, the proposed antenna was designed with CST software. Then, it was fabricated and measured. Measurements show that the gain of the modified antenna is 9.2 dBi, which is 6.2 dBi higher than a conventional antenna.

Broadband High-Gain SIW Horn Antenna Loaded With Tapered Multistrip Transition and Dielectric Slab for mm-Wave Application

A substrate integrated waveguide (SIW) H-plane horn antenna loaded with tapered multistrip transition and dielectric slab is proposed for broadband high-gain operation. The broadband characteristic of the proposed antenna is obtained by loading a tapered multistrip transition. The theory of coupled resonator is introduced to reveal the mechanism of bandwidth enhancement. On the other hand, a dielectric slab is used to enhance the gain of the proposed antenna. The optimal length of this dielectric slab is determined based on the design principles of a dielectric rod with maximum gain. Besides, the tapered multistrip transition also contributes to the gain improvement by suppressing the feed radiation and prompting the transverse expansion of the surface wave. To verify the design theory and concept, a prototype operating at the K- and Ka-bands is fabricated and measured. The measurement results show that the impedance bandwidth of the proposed antenna is from 20.6 to 38.4 GHz (60%). Within the operating band, a peak realized gain of 19.1 dBi and excellent endfire radiation patterns with low cross polarization (<−30 dB) and high front-to-back ratio (FBR >20 dB) are achieved simultaneously. With its broad bandwidth, high gain, low cross polarization, and high FBR, the proposed antenna is promising for various millimeter-wave applications.

Compact Slow-Wave SIW H-Plane Horn Antenna With Increased Gain for Vehicular Millimeter Wave Communication

A substrate integrated waveguide (SIW) H-plane horn antenna with miniaturized longitudinal dimension and increased gain is proposed by loading slow-wave (SW) structures in the form of metallized blind via-holes inside the flare region of the horn for vehicular millimeter wave communications. The slow-wave structure can reduce the phase velocity around the center line of the broad wall and compensate the large phase difference between the center and edge of the aperture caused by reduction of longitudinal length of the horn. Compared with optimum horn with the same aperture width, the gain of miniaturized SIW horn is successfully increased, while the longitudinal dimension is decreased. A SW-SIW horn antenna which covers the 28 GHz band (27.5–28.35 GHz) allocated by Federal Communications Commission for the 5G millimeter wave communications is designed to verify the feasibility of the miniaturized SIW horn antenna facilitated by the proposed slow-wave structure. The SW-SIW horn realizes 53.83% reduction of longitudinal length compared with the optimum horn. The gain of the SW-SIW horn is improved by 1.1 dB on average over 27.5–28.5 GHz compared with optimum horn. A prototype of the proposed SW-SIW H-plane horn antenna is manufactured and measured. The measured results agree well with the simulations.

1‐D reconfigurable graphene‐strips leaky‐wave antenna with different feeders for wide scanning angles

This paper introduces electronic-beam switching graphene-strips leaky-wave antenna (GS-LWA) for THz wireless communications with different feeding structures. The antenna is constructed from graphene-strips printed on silicon oxide substrate with total dimensions of 1350 × 300 × 35 μm3. The graphene tunable conductivity is used to control the GSLWA radiated beam direction without changing its physical structure. A scanning range of 94° (from −68° to 26°) is achieved at 2 THz using different codes. The effect of different plane wave launchers on the radiation characteristics of GS-LWA is investigated. A planar substrate integrated waveguide horn antenna as a plane wave launcher is designed. It introduces a peak gain of 18.2 dBi with a bandwidth of 21.95% and SLL of 10.6 dB. End-fire radiation from parabolic reflector is employed to launch plane-wave in the GS-LWA. A matching BW of 0.82 THz is achieved with peak gain of 18 dBi. A coplanar fed Yagi-Uda like structure element is studied using a single element and two elements array. The two elements array provided the highest matching of −40 dB over BW of 6% and gain of 16.5 dBi. Finally, tapered microstrip line is investigated. It introduced the lowest SLL −16.1 dB with a gain of 17.5 dBi and BW of 39.57% (from 1.5 to 2.24 THz). The selection of proper feeding structure depends on the required matching BW, peak radiated gain, and the lowest SLL. Full-wave analysis of the GS-LWA launched by different feeding methods is introduced.

Four element three‐dimensional SIW horn antenna array for high‐frequency applications

A low-profile three-dimensional substrate integrated waveguide (SIW) horn antenna array with its novel feeding structure is proposed in this article. The feeding element is capable of transforming the wave from one plane to its orthogonal plane. Such type of three-dimensional SIW, H-plane horn antenna design is not available in the existing literature. The design is proposed to provide high gain for radar, 5G, and satellite communication applications. The single SIW horn antenna does not have significant gain at the desired frequencies. When the antenna element is loaded with dielectric the gain improves by 1.4 dB. The antenna elements are further arranged in a box shape, forming a three-dimensional array, which improves the gain significantly. Such structure shows dual band characteristics and provides gain of 11.3 dB at 28.26 GHz and 9.64 dB at 29.41 GHz. The same three-dimensional design when loaded with dielectric at the aperture end also show a dual band behavior and improve the gain further to 12.5 dB at 28.12 GHz and 12.55 dB at 29.28 GHz. The proposed three-dimensional antenna designs are compared to four element linear array designs, and it shows substantial improvement in gain for the desired frequency.

Field‐matching at the compact SIW horn antenna aperture using genetic algorithm

AbstractA compact substrate integrated waveguide (SIW) horn antenna is proposed with improvements in antenna gain and back lobe level. By pixelating the metal part of the antenna aperture and considering the presence or absence of metal in each pixel using Genetic Algorithm (GA), the electromagnetic field distribution could be controlled especially in the front panel of the antenna. As a result, an increase of 4 dBi occurs in gain and back lobe level is 10.8 dB better than the conventional SIW horn antenna. The proposed antenna works at the frequency of 30.2 GHz and without adding any parts to conventional SIW Horn antenna we do not leave the antenna in compact mode. In order to verify the simulation results, two commercial software has been used and the results are good both in CST and HFSS.

A Novel Metamaterial-Based Planar Integrated Luneburg Lens Antenna With Wide Bandwidth and High Gain

A novel metamaterial-based and broadband planar integrated Luneburg lens antenna is designed, fabricated, and measured. A substrate integrated waveguide (SIW) horn antenna is applied as the source to illuminate the operation of the Luneburg lens. In particular, air-via metamaterial structures are loaded in front of the SIW horn aperture to realize broadband performance. Meanwhile, the feeding structure by the SIW horn antenna and the Luneburg lens are integrated through this air-via metamaterial transition. Accordingly, the air-via unit cells are designed and arranged in an array with an equivalent gradient refractive index through diameters to achieve good wave focusing effects. Besides, a good agreement is observed between simulations and experiments. The measured results indicate that a wide bandwidth from 16 to 28 GHz is realized with the return loss below -10 dB. Moreover, high end-fire gains varying from 12.5 to 17 dBi are obtained in the band of 18-27 GHz.

A simple design of SIW horn fed multibeam transmitarray antenna using transmission matrix approach

AbstractThis article develops an efficient solution to design beam‐scanning transmitarray (TA). The four‐layer unit associated with the focal planar substrate integrated waveguide (SIW) array is presented and characterized. The proposed linearly polarized TA is implemented as four‐layer sheet admittance composed of the subwavelength unit, whose transmission feature would be accurate analyzed by the equivalent circuit model. The phase layout of TA is optimized by using the PMM method in order to achieve a wide scanning behavior and reduce the scan loss. Arc‐shaped SIW horn antenna array is adopted as the feeding source. Artificial impedance surfaces printed on either side against the low‐profile substrate results in a greatly enhanced radiation performance. The TA and feeds presented at 20 GHz are both fabricated using standard PCB processing. The measured results show a greatly improved ±45° scan range with the gain loss of 0.73 dBi by switching the SIW horn antenna. Good radiation and bandwidth characters are performed in all states of operation for both ports, confirmed the effectiveness of proposed design process.

A simple design substrate-integrated waveguide horn antenna with reduced back lobe

ABSTRACTA simple technique to design stable gain and low back lobe substrate-integrated waveguide (SIW) horn antenna is proposed. Matching is achieved by placing a metallised via in a specific distance from the aperture of the horn. The proposed design method is based on the analytical equivalent circuit that derived for the impedance of the antenna aperture and the matching metallic via in SIW. The aperture impedance and metallic via in SIW are studied and design curves are extracted for a specified substrate. Also, to reach a directive pattern and reduce the back lobe of the antenna, some chokes are used on the aperture of the horn. The effect of chokes on some parameters such as power flow and radiation pattern, the front to back ratio (FBR), side lobe level (SLL) and increasing directivity of the antenna is reported. The measurement results confirm simulation, appropriately. The proposed structure has high compactness due to the matching technique and design. The proposed SIW horn has compact dimensions as 18.7 * 23.34*7.62 mm (0.93 * 1.16 * 0.37 λ0) and the measured gain of the horn is about 5.5 dB at 15 GHz and bandwidth of six percent.

An SIW Horn Antenna Fed by a Coupled Mode Emulating Pyramidal Horn Antennas

A novel feeding method to dielectric loaded substrate-integrated waveguide (SIW) horn antennas is presented, resulting in equal half power beamwidths (HPBWs) and low sidelobe levels (SLLs) in both the E-plane and H-plane. The concept is to synthesize a unique electromagnetic field distribution using four vertically stacked SIWs. In particular, a uniquely adjusted excitation of magnitudes and phases of the four SIWs is employed as the feeding of the SIW horn, emulating the field distribution of pyramidal horn antennas. This approach realizes the phase correction of the electric field at the horn aperture and concentrates the radiation to the endfire direction to reduce the sidelobes. To prove the concept, a stacked dielectric loaded SIW horn antenna fed by four TE10 excitations was simulated at 35 GHz, yielding a gain of 15 dBi, an HPBW of 33° for both the E-plane and H-plane, and an SLL of approximately -24 dB for both the E-plane and H-plane. To achieve the desired excitation at each port, a narrowband SIW power splitter was designed to adapt a 3.5 mm coaxial connector to the four waveguide ports with the required phase shift. The entire feeding and antenna structure were fully substrate integrated and fabricated on Rogers 5880 panels. The measured radiation patterns show good agreement with the simulation with the best performance at 35.1 GHz.

Substrate Integrated Waveguide Corrugated Horn Antenna

In this paper, a substrate integrated waveguide (SIW) H-plane horn antenna is proposed. We first optimize the antenna in size to obtain the maximum gain. The SIW horn antenna is then corrugated by adding some vias in order to further improve the beam pattern. We use half power beam width (HPBW) as a metric for this improvement. An optimization procedure is also employed to find the best places for the added vias. The horn antenna is implemented on FR4 substrate at 27 GHz frequency band for both with and without corrugation. The results show a good agreement between simulation and measurement. Moreover, it is shown that the SIW corrugated horn antenna reveals a pattern enhancement in terms of HPBW.

Efficient Simulation of Substrate-Integrated Waveguide Antennas Using a Hybrid Boundary Element Method

This paper presents a hybrid boundary element method for the efficient simulation of substrate-integrated waveguide (SIW) horn antennas. It is applicable with good accuracy to relatively thin structures with conventional circular ground vias. In the multiscale simulations, a 2-D contour integral method is used for the modeling of the fields inside the structure with numerous vias and a method of moments is used for the radiated fields outside. The contour integral method is extended in this paper by a new waveguide port of finite size based on the unit cell analysis of an SIW segment. Several SIW horn antennas are studied to validate the proposed method in terms of the input impedance, the field distribution on the aperture, and the radiation diagram. The proposed method shows good to reasonable accuracy and has a numerical efficiency which is about 2–3 orders higher than FEM-based full-wave simulations. It is therefore well suited for fast optimizations.

A compact wideband circularly polarized SIW horn antenna for K band applications

In this manuscript, a compact wideband circularly polarized (CP) substrate integrated waveguide (SIW) horn antenna is presented. The proposed antenna is implemented on a substrate with a thickness of 3.1 mm (0.22 λ0 at 21 GHz central frequency). An antipodal tapered slotted structure is embedded inside the flared part of antenna to obtain a CP converter. The fabricated antenna occupies 36.2 × 27.6 × 3.1 mm3 (2.58 × 1.96 × 0.22 λ03) producing a maximum gain of 11.2 dBi. The measurements of presented antenna exhibit 40% (17–25.5 GHz) relative impedance bandwidth in which the reflection coefficient and axial ratio are below −10 dB and −2.6 dB, respectively. The simulation results are in good agreement with measurements.

Broadband SIW Horn Antenna Loaded With Offset Double-Sided Parallel-Strip Lines

A novel substrate integrated waveguide horn antenna loaded with offset double-sided parallel-strip lines (DSPSL) is proposed in this letter. The severe mismatch between horn aperture and free space leads to narrow impedance bandwidth when the substrate thickness is much smaller than the wavelength (typically less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\lambda _0}$</tex-math></inline-formula> /6). Two groups of periodic offset DSPSL structure are placed in front of the horn aperture, which acts as an impedance transformer to realize smooth transition. Good impedance matching can be easily realized by modifying the constitutive parameters of the offset DSPSL structure. Measured results show that the impedance bandwidth can be improved up to 20.5% from 14 to 17.2 GHz with a low profile less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\lambda _0}$</tex-math></inline-formula> /13. Stable end-fire radiation patterns are obtained across the bandwidth.