Electromagnetic Horn Research Articles

A 3D wideband electromagnetic horn antenna applicator for biomedical applications

Abstract This paper proposes a new, compact, wideband 3D horn antenna for biomedical wireless applications such as cancer and tumor detection. In order to achieve the best penetration level, the antenna has been built and tuned to work in the low frequency range of 0.48–1.24 GHz, which can exhibit a high-resolution detection result. The proposed applicator is a double ridge horn antenna (DRHA). The layout and operation of the key needed components to assemble a wideband hyperthermia system are provided in this study. We assume a cylindrical human tissue phantom with wideband dispersive tissue properties, and simulation results are given. The resulting field maps are displayed in several planes to illustrate the energy localization process. The findings indicate that, in contrast to traditional narrowband systems, wideband operation may improve energy localization in deep tumor locations while eliminating hot spots. The suggested antenna was built and measured to verify the result.

Early Pioneers of Electromagnetic Horns: From 1880 to 1960 [Historically Speaking

Early Pioneers of Electromagnetic Horns: From 1880 to 1960 [Historically Speaking

Ultrawideband 3-D Printed Endfire TEM Horn Antenna Mounted on a Cylinder Conductor

An ultrawideband, three-dimensional (3-D) printed end-fire transverse electromagnetic (TEM) horn antenna mounted on a cylinder conductor is proposed. The system consists of four TEM horn antennas and a cylinder conductor. The proposed TEM horn antenna is composed of four parts: a metal exponential curve, a trapezoidal metal top cover, a cylindrical ground, and a metal ridge. To enhance impedance bandwidth and radiation characteristics, a metal ridge is introduced on the cylinder ground plane. To verify the proposed antenna, a prototype is 3-D printed with surface metallization. The proposed antenna has a broad bandwidth from 1 to 16 GHz (16:1) with a voltage standing wave rate (VSWR) < 2 and a profile of 0.134λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> being the free-space wavelength at the lowest frequency). A good radiation pattern is obtained over the impedance bandwidth, and the measured gain ranges from 3.5 dBi to 11.5 dBi.

Design and development of half impulse radiating antenna based ultra wide band system

Abstract An ultra wide band system utilizing Half Impulse Radiating Antenna topology has been designed and developed. A compact Marx generator and a solid dielectric pulse forming line fed the antenna. Based on pulse parameters, frequency range of 250 MHz–1250 MHz is chosen for antenna design. Analytical equations and CST Microwave Studio are used for design and analysis of the Antenna and ultra wide band system. Maximum electric field of 11 kV/m at 20 m distance from source has been measured using half-transverse electromagnetic horn type sensor. This paper discusses both time domain and frequency domain results for the designed UWB system. A good agreement between the simulated and the measured power pattern has been demonstrated in this paper.

Ultra‐wideband directional electrically small antenna for UHF through C‐band 5G and beyond 5G applications

AbstractA semi‐spherical combined transverse electromagnetic (TEM) horn and loop antenna is designed for directional ultra‐wideband operation from 0.42 to 6 GHz for 5G and beyond 5G applications across military and commercial sectors. The antenna structure fits within a sphere with 3‐cm radius, thus operating as electrically small over the lower part of the band (ka = 0.5 at 0.795 GHz and ka = 1 at 1.59 GHz). To spread the currents across the volume while maintaining the required relationship between the lowest order TE and TM modes, the loop section is modified to conform with the enclosing minimum sphere. The TEM horn, bowtie, and resistive loading are then tuned to achieve improvement over the conventional topology in the radiation efficiency by &gt;7% when ka = 0.5 and &gt;22% when ka = 1.

Beam shaping for magnetoelectric transverse electromagnetic horn by using gradient refractive index lens

AbstractThis paper presents a new type of flat gradient index lens used for the beam shaping of a miniaturized magnetoelectric transverse electromagnetic (ME‐TEM) horn antenna. Novel metamaterial unit cells with variable sizes are proposed to achieve high refractive index distribution. After applying the novel meta‐lens to the modified transverse electromagnetic horn, the inherent E‐plane beam squint of the low‐profile ME‐TEM horn is corrected. The radiation patterns in E‐plane and H‐plane are focused and the peak gain at 4 GHz is improved to 17.3 dBi. The dB matching bandwidth of 0.4–4 GHz is achieved while the measured is a little poor at 0.8 GHz. The length of the total antenna is still shorter than half of the largest wavelength. The application potential of the gradient index meta‐lens in the low‐frequency band is verified.

High power balanced TEM horn antenna for ultra wide band radiator

AbstractA balanced transverse electromagnetic (TEM) horn type antenna is designed and developed for a 120 kV, 66 Ω high power ultra wideband (UWB) radiator. This antenna consists of a coaxial to parallel plate unzipper BALUN followed by an exponentially tapered TEM horn structure. Analysis of this antenna in time and frequency domain is performed using CST Microwave Studio. This antenna is having a power handling capacity of 1000 MW, with percentage bandwidth of 167%. This antenna has a gain of ~10 dB at 1 GHz frequency. Return loss performance of better than −10 dB is observed in 150 MHz to 1 GHz frequency range. Effective radiation of short pulses (&lt;5 ns) with very fast rise time (300–500 ps) has been demonstrated using this high‐power antenna. Practical results at 220 MW power are presented in this article. Directional performance of this antenna is practically established through peak power patterns in horizontal and vertical plane.

A Compact Machine Learning Architecture for Wideband Amplitude-Only Direction Finding

A generalized, reduced-size machine learning architecture for single-snapshot amplitude-only direction finding (AODF) is proposed for uniform circular arrays. A method for reusing angle of arrival (AoA) estimation models that are accurate over narrower fields of view is described. The efficacy of the proposed method is demonstrated using an ultrawideband circular array of miniaturized transverse electromagnetic (TEM) horns covering 1.5–5.5 GHz. Reasonable azimuth estimations performed on this retrofitted system are obtained over 2.6:1 bandwidth (1.5–4.0 GHz). Antenna performance features that impact the accuracy of AODF are also recognized. Root mean square error less than 5° is achieved in simulation above 15 dB signal-to-noise ratio (SNR) and above 20 dB SNR in measurement. The improved accuracy over the conventional correlation method of 52%–85% is demonstrated in an SNR domain of 10–40 dB. This performance improvement is obtained while maintaining a footprint reduction of 80%–95%, and an AoA estimation time speed-up of at least 85%.

A wide Bandwidth Pyramidal Horn Antenna with Enhanced Gain Using Metasurface layer

A new design of a pyramidal horn antenna operating at 8-18 GHz based on the waveguide structure is presented in this paper. A metasurface layer, which consists of a set of periodic unit cells, is employed on the E-plane walls of the horn antenna. This is to enhance the realised gain and bandwidth. The unit cell shape is chosen based on the cavity resonator theory. The design method of the unit cells is analyzed and presented here using the Computer Simulation Technology (CST) microwave studio. The scattering parameters of a single unit cell are optimised in order to operate it at the designed operating frequencies. Compared to a conventional pyramidal horn, the proposed horn antenna gain improves up to 10 dBi. The peak gain is 23.7 dBi and the reflection coefficient at S11= -10 dB is 5%. The radiation patterns are well shaped, and are stable over a large operating frequency range. The proposed pyramidal horn antenna is relatively low profile and may be of interest in satellite communication systems. References ABDULKARIM, Y. I., AWL, H. N., MUHAMMADSHARIF, F. F., KARAASLAN, M., MAHMUD, R. H., HASAN, S. O., IŞıK, Ö., LUO, H. &amp; HUANG, S. 2020. A low-profile antenna based on single-layer metasurface for Ku-band applications. International Journal of Antennas and Propagation. ASL, A. N., YOUSIF, B. &amp; AL-ZALABANI, M. 2020. Design, modeling, and fabrication of a new compact perfect metamaterial X-band absorber. AIP Advances, 10, 025328. CHEN, H.-T., TAYLOR, A. J. &amp; YU, N. 2016. A review of metasurfaces: physics and applications. Reports on progress in physics, 79, 076401. CHEN, X. &amp; GE, Y. 2017. Enhancing the radiation performance of a pyramidal horn antenna by loading a subwavelength metasurface. IEEE Access, 5, 20164-20170. CHU, L. &amp; BARROW, W. 1939. Electromagnetic horn design. Electrical Engineering, 58, 333-338. ESSELLE, K. P. 2007. A low-profile compact microwave antenna with high gain and wide bandwidth. IEEE transactions on antennas and propagation, 55, 1880-1883. GE, Y., LIN, C. &amp; LIU, K 2018. A Metasurfaced Pyramidal Horn Antenna for Circularly-Polarized Applications. IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP), IEEE, 517-518. GE, Y., SUN, Z., CHEN, Z. &amp; CHEN, Y.-Y. 2016. A high-gain wideband low-profile Fabry–Pérot resonator antenna with a conical short horn. IEEE Antennas and Wireless Propagation Letters, 15, 1889-1892. LI, Y., GE, L., WANG, J., DA, S., CAO, D., WANG, J. &amp; LIU, Y. 2019. 3-D printed high-gain wideband waveguide fed horn antenna arrays for millimeter-wave applications. IEEE Transactions on Antennas and Propagation, 67, 2868-2877. LIER, E. &amp; SHAW, R. 2008. Design and simulation of metamaterial-based hybrid-mode horn antennas. Electronics letters, 44, 1444-1445. LIN, C., GE, Y., BIRD, T. S. &amp; LIU, K. 2018. Circularly polarized horns based on standard horns and a metasurface polarizer. IEEE Antennas and Wireless Propagation Letters, 17, 480-484. MARHEFKA, R. J. &amp; KRAUS, D. 2002. Antennas for all Applications. Antennas for all applications. MAYBELL, M. J. &amp; SIMON, P. S. 1993. Pyramidal horn gain calculation with improved accuracy. IEEE transactions on antennas and propagation, 41, 884-889. MORADI, A. &amp; MOHAJERI, F. 2017. Side lobe level reduction and gain enhancement of a pyramidal horn antenna in the presence of metasurfaces. IET Microwaves, Antennas &amp; Propagation, 12, 295-301. PAN, B., LI, Y., PONCHAK, G. E., PAPAPOLYMEROU, J. &amp; TENTZERIS, M. M. 2009. A 60-GHz CPW-fed high-gain and broadband integrated horn antenna. IEEE Transactions on Antennas and Propagation, 57, 1050-1056. WANG, P., WU, Q., HE, R.-B. &amp; LUO, W. 2019. Gain and radiation pattern enhancement of the H-plane horn antenna using a tapered dielectric lens. IEEE Access, 7, 69101-69107. WU, Q., SCARBOROUGH, C. P., GREGORY, M. D., WERNER, D. H., SHAW, R. K. &amp; LIER, E. Broadband metamaterial-enabled hybrid-mode horn antennas. 2010 IEEE Antennas and Propagation Society International Symposium. IEEE, 1-4. WU, Q., SCARBOROUGH, C. P., WERNER, D. H., LIER, E. &amp; SHAW, R. K. 2013. Inhomogeneous metasurfaces with engineered dispersion for broadband hybrid-mode horn antennas. IEEE transactions on antennas and propagation, 61, 4947-4956. WU, Q., SCARBOROUGH, C. P., WERNER, D. H., LIER, E. &amp; WANG, X. 2012. Design synthesis of metasurfaces for broadband hybrid-mode horn antennas with enhanced radiation pattern and polarization characteristics. IEEE transactions on antennas and propagation, 60, 3594-3604.

Antenna Array with TEM-Horn for Radiation of High-Power Ultra Short Electromagnetic Pulses

An antenna array with short shielded transverse electromagnetic horns (S-TEM-horns) for emitting high-power radiation of ultra-short electromagnetic pulses (USEMP) has been created and researched. The antenna unit consists of an ultra-wideband antenna array with four S-TEM horns, with each connected to a two-wire HF transmission line, and these four lines are connected to an antenna feeder. This feeder is connected to a semiconductor generator with the following parameters: a 50 Ohm connector, 10–100 kV high-voltage monopolar pulses, a rise time of about 0.1 ns, FWHM = 0.2–1 ns, and pulse repetition rates of 1–100 kHz. The antenna array was designed and optimized to achieve a high efficiency of about 100% for the antenna aperture by using a 2 × 2 array with S-TEM-horns, with shielding rectangular plates for the return current. The transient responses were studied by simulation using the electromagnetic 3D code “KARAT” at the time domain and experimentally with the use of our stripline sensor for measurement of the impulse electrical field with a 0.03 ns rise time and a 7 ns duration at the traveling wave. The radiators were emitting USEMP waves with a hyperband frequency spectrum of 0.1–6 GHz. The radiation with an amplitude of 5–30 kV/m of the E-field strength at a distance of up to 20 m was successfully applied to test the electronics for immunity to electromagnetic interference.

A transient electromagnetic disturbance testing system based on low-frequency-compensated symmetric TEM horn antenna.

A transient electromagnetic disturbance (TED) testing system with an adjustable direction of polarization is developed in terms of a low-frequency-compensated symmetric transverse electromagnetic (TEM) horn antenna in this paper. TEM horn antennas are deficient in the low-frequency radiation, which would lead to a very narrow pulse width and cannot be directly applied in radiation tests of TED, especially the TED with abundant low-frequency components such as fast transient overvoltage and high-altitude electromagnetic pulse. To address this problem, a theoretical radiation model and a design principle of the back-loading method are proposed to compensate for the low-frequency performance. After the optimization of the structure according to the simulated results, a TED testing system with the aperture width of 0.9 m and the length of 1.8 m is built. The rise time of the electric field measured at the center of the aperture is 2.39 ns, the pulse width is 27.65 ns, and the peak field is over 50 kV/m, which can meet the requirements of relative standards. The dimension of the working volume is estimated as 0.4 × 0.5 × 0.5 m3 according to the field distribution.

A 3‐D Printed PCB Integrated TEM Horn Antenna

AbstractThis paper presents a very broadband (5–40 GHz) novel three dimension (3‐D) printed Transverse ElectroMagnetic (TEM) horn antenna. It is integrated with a planar Printed Circuit Board and radiates in a perpendicular direction of the Printed Circuit Board. The described antenna provides benefits in terms of cost and size for a two dimensional antenna array. Here the antenna and its corresponding transition to a regular 50 Ω microstrip line through Parallel Plate Waveguide and a 90° bend are presented. Prototypes of back‐to‐back transitions and antenna are fabricated and measured. The antenna has a return loss below −10 dB and a gain of approximately 10 dBi over the targeted frequency range.

Transient linear TEM horn array

This study presents an ultrawideband transverse electromagnetic (TEM) horn array with enhanced frequency- and time-domain performances for high-power transient and short-pulse radiation applications. The proposed linear array is composed of five combined TEM horn and loop elements. The compact size, wideband performance, and low-dispersion characteristics of the utilised element enable good time and frequency operations over more than two-octave bandwidth. The performance of the designed array is characterised computationally and experimentally. The scanning capabilities are also demonstrated; particularly for the time-domain operation using fidelity factor and energy patterns. Moreover, conventional frequency-domain side lobes (SLL) reduction techniques are utilised to minimise the time-domain radiation at undesired directions. The proposed array has VSWR 8 dBi, good quality radiation patterns, and SLL<−10 dB over more than 4:1 bandwidth. Excellent time-domain performance demonstrated by high fidelity factor over the array's field of view is achieved. Time-domain scan up to 40° is also demonstrated.

A numerical approach for the analysis of car snail horn performance

A car horn is a safety device present on every type of vehicle as a warning system. Standard CEE-ECE 70/388 gives the minimum performance requirements in terms of the sound emission a car horn must guarantee outside the vehicle. At the same time, car horns with higher performance are required because of increased noise treatment in the engine compartment. With this in mind, the aim of the proposed research is to optimize and maximize the sound emission of commercial car horns. In this paper, an acoustical finite element model is presented and discussed to determine the cavity modes of the snail horn and to predict the sound pressure emitted outside the horn for an acoustical source excitation. After validation of the proposed numerical approach, the actual geometry of the snail was modified in accordance with an optimization scheme using an automated procedure. The objective of the complete procedure is to increase the emitted sound pressure as well as a set of cavity modes that are well coupled with fundamental working frequencies and with the first harmonic characteristic of the electromagnetic horn housing. Several numerical models are presented and validated against experimental tests

Ultrawideband TEM Horn Circular Array

An eight-element circular array of miniaturized combined transverse electromagnetic horn and loop elements for joint frequency and time operation is presented. The use of such ultrawideband and compact directional element leads to stable wideband radiation patterns with moderate gain for omnidirectional phase mode 0 of operation. Moreover, a directional mode enabled by simply exciting specific element(s) in the array is also demonstrated. Obtained directional beams can be steered to a desired direction in horizontal plane simply by exciting an appropriate element. Low dispersion of the utilized element permits distortionless pulse radiation for both modes of operation. The performance of the proposed array is characterized computationally and experimentally in frequency and time domains for both modes. The fabricated circular array has VSWR 10 dB) radiation characteristics, nominal gain >6 dBi, cross polarization level <−15 dB, and excellent time-domain performance with high-fidelity factor over more than two octaves.

Ultrawideband Flush-Mounted Antenna

A wideband compact antenna that can be flush mounted on a platform for high-power broadside transmitting applications is introduced. The proposed design comprises a transvers electromagnetic (TEM) horn embedded in a shaped rectangular cavity. The detrimental interaction with the lossless cavity is mitigated by properly integrating the TEM horn inside the cavity. This approach allows the antenna to radiate as an aperture antenna at low frequencies while maintaining good radiation features from the TEM horn at higher frequencies. Elliptically shaped ridges are also added inside the cavity to improve gain and the quality of radiation patterns at the high-frequency end. The proposed antenna has electrical size of ∼0.28 $\lambda $ × 0.54 $\lambda $ × 0.3 $\lambda $ (length × width × depth) at the turn-on frequency and has VSWR 5 dBi, and good radiation patterns with low cross polarization from 2 to 7 GHz.

An Active 20-MHz to 2.5-GHz UWB Receiver Antenna System Using a TEM Horn

An ultrawideband receiver antenna system is proposed. The radiating element is a transverse electromagnetic horn antenna, featuring a negative impedance converter at lower frequencies. The voltage standing-wave ratio (VSWR) is less than 2.0 in the bandwidth from 20 MHz to 2.5 GHz. A good agreement between the measurements of the fabricated system and the simulated results is observed. Sample applications include direction finding, broadband communication systems, radar systems, and electromagnetic compatibility measurement systems.

Miniaturization of TEM Horn Using Spherical Modes Engineering

The spherical mode expansion is exploited to miniaturize a transverse electromagnetic (TEM) horn antenna and achieve good frequency and time domain performances. To adjust the radiated powers of fundamental transverse electric and transverse magnetic modes, the combined loop and TEM horn antenna is engineered. The constructive combination of the two modes below the horn’s turn-on frequency miniaturizes the antenna and improves its gain. The magnitude and phase tuning of the desired modes is achieved by modifying the loop’s geometry. The spherical modal spectrum at higher frequencies is also studied and the antenna’s geometry is further modified to maintain constructive interference between the higher order spherical modes. A prototype with electrical size of $0.188~\lambda ~\times0.145\lambda ~\times0.087\lambda $ (length $\times $ width $\times $ height) at the turn-on frequency is fabricated over a ground plane. Over three times lower turn-on frequency is obtained compared to a conventional TEM horn with up to 9 dB improvement in the realized gain at the low end and better radiation characteristics over more than 5:1 bandwidth (from 0.87 to 4.5 GHz). Unidirectional operation with front to back ratio >9 dB and excellent time-domain performance with fidelity factor >95% over wide field of view are also demonstrated.

Horn antennas with enhanced functionalities through the use of frequency selective surfaces

In this work, realizations of a dual function integrated modules are simply built by fixing the identical frequency selective surface (FSS) s into the apertures of the available exponentially tapered transverse electromagnetic (TEM) and ridged horn antennas. Both modules are confirmed experimentally to have functions of prefiltering suppressing EMI and noise when the signal is received, alongside the enhanced directivity in the desired band, thus these modules can be called as “Filtennas.” A FSS is simply built by the properly designed periodic double anchor-shaped microstrip patches in CST microwave suit using low-cost FR4 with the relative permittivity 4.4, thickness 1.58 mm, loss tangent 0.0035. From the measured results, it can be found that the proposed modules keep mismatching characteristics of the horn antennas, meanwhile their gains and beamwidths are enhanced to amplify the signal in the desired band and simultaneously deteriorated to attenuate EMI and noise in the out-band. It is expected that this methodology can be implemented to effectively reduce volume and cost of communication systems. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:287–293, 2016.

Design of UWB Antenna for Air-Coupled Impulse Ground-Penetrating Radar

This letter presents a new transverse electromagnetic flared horn antenna for the demanding requirement of an air-coupled impulse ground-penetrating radar. Structure anatomy is performed focusing on achieving good impedance matching throughout the wide frequency band. The design procedure starts with constructing an analytic model to evaluate the preliminary physical dimensions to achieve minimum reflections. Structural fine tunings are then performed for optimization. The antennas are fabricated and tested. Experimental results validate the design effectiveness.