Optimum Horn Research Articles

Wideband and Miniaturized Phase-Corrected Empty Substrate-Integrated H-Plane Horn Antenna for 5G Millimeter Waves

This paper introduces a substrate integrated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -plane horn antenna with phase-corrected structures. The quadratic curves etched on the horn aperture improve the impedance matching and the gain performance. The quasi-uniform phase distribution is achieved by the phase-corrected structure which consists of the quadratic curves and metallized via-holes embedded symmetrically on the top and bottom layers. To integrate with other planar circuits and test the proposed antenna, the transition from microstrip line to empty substrate-integrated wave guide (ESIW) is used. Compared with the optimum horn, the proposed antenna realizes a 60% reduction of the longitudinal length. A wide impedance bandwidth of 22% for |S11|<– 10dB which covers the n257, n258, and n261 5G frequency bands (24.25–29.5 GHz) is verified by a fabricated prototype. Moreover, the stable realized gain varying from 9.3 to 11 dBi is obtained during the operating bandwidth.

Gain Enhancement of Horn Antenna Using a Metal Lens

A compact wideband open-horn antenna is proposed for point-to-point wireless communications. The antenna consists of a spatial power divider and an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H$ </tex-math></inline-formula> -plane lens. Both the power divider and lens are metallic, fabricated by using 3-D-printing technology. Our proposed lens has wrinkled subchannels of different lengths to convert the original quasi-cylindrical wavefront into a nearly planar wavefront across a wide frequency range, giving a wideband high-gain antenna. The operating principle and the design guideline are given. Using the guideline, two design examples with different <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E$ </tex-math></inline-formula> -field magnitude distributions are studied and fabricated for Ku-band applications. The first design has a uniform <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E$ </tex-math></inline-formula> -field magnitude distribution, with its maximum measured gain and normalized sidelobe level (SLL) being 18.1 dBi and −9.4 dB, respectively. The second design has a tapered <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E$ </tex-math></inline-formula> -field magnitude distribution. In this case, the maximum measured gain and normalized SLL are 19.6 dBi and −15.0 dB, respectively. The overall measured 3-dB gain bandwidths of the two designs are more than 46.7%. It is found that the sizes (axial lengths) of the proposed designs are smaller than those of optimum horn antennas by more than 60%.

Size reduction of a conical horn antenna loaded by multi‐layer metamaterial lens

In this paper, a conical horn antenna in the presence of a metamaterial lens in the X-band is introduced and fabricated. The annular metamaterial lens is located at the aperture of a shortened horn antenna, whose length is half the length of the corresponding optimum horn. The phase velocity in the metamaterial lens is more than the phase velocity along the axis of the antenna for the same propagation distance, so the phase distribution at the aperture of the antenna is uniform and the gain of the shortened horn antenna increases. Metamaterial cells are designed in the form of a printed circuit board that have easy to build and suitable cost. The design process is based on how the waves incident on the proposed metamaterial cell, and finally, by using the particle swarm optimisation (PSO) algorithm proper radiation characteristics in the desired frequency range can be achieved. The radiation characteristics of an antenna with a metamaterial lens are similar to that of an antenna with optimum length in the desired frequency band. The difference is that the weight and volume of these antennas are reduced, so they have better performance in satellite and radar systems.

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.

W‐band flat lens antenna with compact size and broadband performance

A broadband short-length lens antenna operating in W band is presented in this study. The lens is composed of a dielectric host material with numerous variable square holes drilling on it, which is fabricated using the three-dimensional printing method with high accuracy and low cost. Then, the lens is mounted directly on the end of a length-shortened horn antenna, obtaining a compact lens antenna. Phase variations of the dielectric unit-cell under different oblique incidences are taken into consideration while constructing the lens. Simulation results reveal that gain enhancement of about 1 dB is achieved compared with the designs using the conventional method. Effects of lens height on antenna radiation performances are also studied and the lens profile is reduced to half with little performances deterioration. For the total lens antenna, a maximum gain of 23.2 dBi is measured at 94 GHz, which reveals 7.4 dB gain enhancement compared with the feed source. The measured 1 and 3 dB gain bandwidths are 13.8 and 37.8%, respectively. The proposed lens antenna shows a profile reduction of 42.3% with respect to the optimum horn while exhibiting comparable gain performance within a broad frequency band.

Broadband Compact Horn Antennas by Using EPS-ENZ Metamaterial Lens

We present the design of a flat lens, made by a conventional material and an epsilon near-zero metamaterial, to plug up the aperture of a short horn antenna, in order to achieve radiation performances similar to the ones of the corresponding optimum horn over a broad frequency range. Lens operation is based on the phase-compensation concept: phase-fronts of the field propagating along the short flare of the horn propagate with different phase velocities in the two lens materials, resulting in an uniform phase distribution on the aperture. Starting from the theoretical study of the transmission properties of a bulk epsilon near-zero slab, we derive the analytical formulas for the design of the flat lens and validate them through full-wave numerical simulations. Then, a realistic version of the lens, realized with a wire-medium and exhibiting a near-zero real part of the effective permittivity in the frequency range of interest, is presented. Considering two examples working in the C-band, we show that the lens can be designed for both conical and pyramidal horn antennas. In both cases, the length of the horns is half the one of the corresponding optimum versions, while the obtained radiation performances are similar to those of the optimum horns over a broad frequency band. This result may open the door to several interesting applications in satellite and radar systems.

A Simpler Version of Optimum Horn Design Equations for Classroom Use [Education Column

The subject “Advanced Radiation Systems,” offered by the Anna University, Chennai (Madras), for masters students has optimum pyramidal horn design as one of the topics. While preparing lecture material for this topic based on [1-4], this author thought it might be desirable to present a simpler version of the equations that could be somewhat easier to remember (in case there was a requirement), and could possibly facilitate at least marginally easier calculations in the classroom. The equations that follow are a result of this thinking.

Mapping speed for an array of corrugated horns

I address the choice of horn diameter for millimeter-wave array receivers with corrugated horns. For maximum point-source mapping speed, in both total power and polarization with typical receiver noise contributions and a close-packed horn array that fills the field of view, the optimum horn diameter is 1.6-1.7Flambda, where F is the focal ratio. A +/-25% change in horn diameter gives <10% degradation in mapping speed. Correlated noise from the cold stop, atmosphere, and cosmic microwave background has little effect on the mapping speed and optimum horn diameter.

3D-feed horn antenna-coupled microbolometer

Abstract In this paper, we proposed a microbolometer coupled with 3D feed horn antenna. It is a new device that enhances the performance of the microbolometer by coupling 3D horn shape antenna. We designed the optimum horn antenna size that has 20.08 dB directivity. And we designed the microbolometer as a circular shape in order to reduce the coupling loss between the horn antenna. We confirmed that the detectivity of the designed microbolometer would be improved as the noise characteristics of the microbolometer are enhanced by coupling feed horn antenna which acts as a cold shield. The detectivity of the designed 3D antenna-coupled microbolometer was improved about seven times more than that of the conventional microbolometer in state of background limited infrared performance. Fabrications of the microbolometer are carried out by a surface micromachining method. We achieved the thermally good isolated floating structure. And the 3D feed horn antenna was constructed by using a mirror-reflected parallel beam illuminator (MRPBI) system which is invented for rotating and tilted illumination. Using this method, we acquired the feed horn shape antenna mold. And we also acquired antenna plate by using PDMS injection method. Finally, to couple the antenna and the microbolometer, we proposed the PDMS injection bonding method.

Optimum geometry and performance of a dual-mode horn modification

We have carried out the optimization of the simplest dual-mode horn that does not include the special cylindrical phasing section. Calculation of the horn characteristics has been performed by using a stepped representation of the conical section, with a subsequent application of the method of generalized scattering matrices, which more accurately accounts for all of the effects taking place when exciting the horn, The objective of the optimization has been the minimization of the maximum crosspolar level. The optimum horn parameters obtained as a result, and the corresponding radiation characteristics, can serve as additional reference information in the development of antenna systems using dual-mode horns.

Scales for rectangular horns

The scales presented are useful both for design of optimum horns for a given gain, and for finding the gains of rectangular horns from the dimensions. This article further illustrates the relationships among various parameters of rectangular horns. Although the design method started with a waveguide width-to-height ratio of 2:1, the method produces suitable designs for other waveguide ratios.

Microwave radiation for control of Tribolium confusum in wheat and flour

Abstract The susceptibility of Tribolium confusum Jacquelin du Val to microwave energy was determined by irradiating vials of infested wheat or flour near the aperture of an optimum gain horn coupled through a waveguide to a magnetron operating at 8·5 GHz and 30 W average output at a pulse repetition frequency of 4000 Hz. Mortality was a function of exposure time and wheat moisture content. Adult mortality was higher in insulated samples of wheat than in non-insulated samples. Susceptivility of stages to radiation at 60°C was: eggs > pupae > adults > larvae. Survival of pupae near the surface of wheat indicated that heat was distributed non-uniformly. Mortality was higher in wheat than in white flour. Adults from 1·5 to 7 months old were equally susceptible to radiation.

Radiation of conical horns excited in higher-order modes

Theoretical investigations carried out for the far-field-radiation-pattern prediction of conical horns excited in the spherical TMmn and TEmn modes are applied on the radiation-pattern analysis of TM01 and TE01 modes. The results, valid even for conical horns with large flare angles, provide an optimum horn design for a maximum gain slope near the boresight axis.

Radiation characteristics of a waveguide excited dielectric sphere backed by a metallic hemisphere

The experimental results of the radiation characteristics of waveguide excited dielectric spheres backed by metallic hemispheres are reported. The test antenna consists of a dielectric loaded hemispherical horn excited by a circular waveguide. The test data have shown that such a structure produces a radiation pattern with low sidelobe levels, increased on-axis gain, and reduced 3 dB beamwidth as compared to a waveguide excited dielectric sphere of same diameter and an optimum horn having an aperture of identical cross section area. Also, it presents a low VSWR over the waveguide band.

Radiation characteristics of waveguide-excited dielectric spheres with matched sphere-air boundary

The results of experiments on the radiation characteristics of circular-waveguide-excited dielectric spheres with matched sphere-air boundaries are reported. The test data have shown that a waveguide-excited dielectric sphere, backed by a metallic hemisphere and with simulated quarter-wavelength matching at the dielectric–air boundary through surface perturbations, produces a directive pattern with a low side-lobe level, increased on-axis gain and reduced 3 dB beam-width, as compared with a simple wavegudie-excited dielectric sphere of the same diameter and an optimum horn with an aperture of identical cross-sectional area. Also, it presents a low voltage standing-wave ratio over the waveguide band.

Waveguide excited dielectric spheres as feeds

The results of experiments with dielectric obstacles of various geometries placed directly upon the apertures of circular and rectangular waveguides are presented. It is found that dielectric spheres, and in some instances dielectric cubes, two to four wavelengths in dimension produce directive patterns with low sidelobe levels. For some cross sections, the measured gain of these antennas is greater (6 dB in some cases) than that produced by optimum horns having apertures of identical cross section. The linearity of the polarization of these antennas is essentially the same as that of an open-end waveguide antenna.

Radiation properties of conical scalar horns

It is shown that the eigenvalues, which are derived in a closed form from a simpler solution, associated with balanced hybrid modes in conical scalar horns are close (within 4%) to the exact values obtained numerically by Clarricoats for the first ten modes. It is verified that the simpler expressions obtained for the far-field radiation patterns of conical scalar horns, supporting the balanced HE11 mode, closely follow the available experimental results for several values of α0 (half the flare angle), including the case α0 = 90°. From a study of the variation of the on-axis gain with the significant dimensions of the horn, an empirical relation for determining the dimensions of optimum scalar horns is obtained.

Optimum paraboloid aerial and feed design

A computer study was made of the spillover, crosspolarisation and illumination efficiency of paraboloids of various focal-length/paraboloid-diameter (F/D) ratios, fed by rectangular, square and circular wave-guides in their lowest-order modes. The feed radiation patterns used were those derived by simple diffraction theory from the incident waveguide-mode field distribution. The approximations made in this derivation give unnaturally low spillovers for very small aperture feeds, and thus favour short F/D systems, which would use such feeds. The feed dimensions were optimised to give a maximum figure of merit (gain/total noise temperature) for each combination of feed, receiver noise temperature and F/D ratio. Some of the optimum horn dimensions and resulting illumination tapers, excess aerial noise temperatures, gain efficiencies and figures of merit produced by the computations are presented. The results show, among other things, that the figure of merit of a F/D-ratio system. about 0.8dB less than that of a large-F/D-ratio system They also show that, if the system has a low receiver temperature, the feed dimensions should be larger than conventional design procedures indicate, to give up to 3dB more edge-illumination taper

Modifications of horn antennas for low sidelobe levels

A modified horn antenna with significantly reduced backlobes over nearly a two-to-one frequency band is discussed. This horn has a well-defined phase center at its apex, and the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</tex> - and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> -plane patterns are nearly identical over the frequency band if the horn has a square (or circular) aperture. Horns considered cover a wide range of flare angles and include one which fits the criterion for the optimum horn at the lower end of the operating frequency band. The VSWR is less than 1.2 over most of the frequency band.

Some data for the design of electromagnetic horns

Using an idea recently suggested by the author,1 a table is presented from which the gain of all electromagnetic horns may be calculated with substantially the same accuracy obtainable using the gain formula. The exact parameters of an optimum horn are given, and a simple procedure for the design of optimum horns with a specified gain and other desirable properties is described.