Low profile, broadside radiating, electrically small huygens source antennas

© 2015 IEEE. It is demonstrated numerically that a metamaterial-inspired, low profile (height approximately A/80), electrically small (ka = 0.45) Huygens source antenna can be designed to radiate at 300 MHz in its broadside direction with a high radiation efficiency and a large front-to-back ratio. Two electrically small, near-field resonant parasitic (NFRP) antennas are first designed. Both are based on a coax-fed dipole antenna. An electric dipole response is obtained by combining it with a tunable Egyptian axe dipole (EAD) NFRP element. A magnetic dipole response is obtained by spatially loading the driven dipole with tunable, extruded capacitively loaded loop (CLL) NFRP elements. The driven dipole and the EAD and CLL NFRP elements are combined together and retuned to achieve a broadside radiating Huygens source antenna. Two different designs, one with two CLL elements and one with four, are obtained, and their performance characteristics are compared

Design and Testing of Simple, Electrically Small, Low-Profile, Huygens Source Antennas with Broadside Radiation Performance

© 2016 IEEE. The efficacy of a simple, electrically small, low-profile, Huygens source antenna that radiates in its broadside direction is demonstrated numerically and experimentally. First, two types of electrically small, near-field resonant parasitic (NFRP) antennas are introduced and their individual radiation performance characteristics are discussed. The electric one is based on a modified Egyptian axe dipole NFRP element; the magnetic one is based on a capacitively loaded loop NFRP element. In both cases, the driven element is a simple coax-fed dipole antenna, and there is no ground plane. By organically combining these two elements, Huygens source antennas are obtained. A forward propagating demonstrator version was fabricated and tested. The experimental results are in good agreement with their analytical and simulated values. This low profile, ∼0.05λ0, and electrically small, ka = 0.645, prototype yielded a peak realized gain of 2.03 dBi in the broadside direction with a front-to-back ratio of 16.92 dB. A backward radiating version is also obtained; its simulated current distribution behavior is compared with that of the forward version to illustrate the design principles

Metamaterial-inspired Electrically Small Platforms: Enhanced Directivity Properties

© 2018 IEEE. A variety of near-field resonant parasitic (NFRP) antennas have been developed as electrically small platforms to realize high directivity. These include compact arrays and Huygens dipole and multipole radiating systems. A brief review of these developments and their scattering equivalents will be presented

Dual-linearly polarized, electrically small, low-profile, broadside radiating, huygens dipole antenna

© 1963-2012 IEEE. A dual-linearly polarized, electrically small, low-profile, broadside radiating Huygens dipole antenna is presented, that is, an advanced combination of electric and magnetic near-field resonant parasitic elements. Its prototype was fabricated and tested. The measured results are in good agreement with their simulated values. At 1.515 GHz, the prototype is electrically small ( ka = 0.904 ) and low profile ( 0.0483\lambda -{0} ). It exhibits high port isolation and a large front-to-back ratio (FTBR). The isolation between its two ports is demonstrated to be over 25.8 dB within its -10 dB fractional impedance bandwidth, 0.46%. When port 1 (port 2) is excited, the peak realized gain is 2.03 dBi (2.15 dBi) strictly along the broadside direction with a 12.4 dB (12.1 dB) FTBR

Overcoming traditional electrically small antenna tradeoffs with meta-structures

© 2017 Euraap. Metamaterial-inspired near-field resonant parasitic (NFRP) electrically small antennas (ESAs) have been designed and experimentally validated to have not only high radiation efficiencies, but also multi-functionality, large bandwidths, high directivities and reconfigurability. These expanded capabilities have been attained by introducing more complex meta-structures, i.e., multiple NFRP elements loaded with fixed and tunable lumped elements, as well as active circuits. Different classes of passive and active NFRP ESAs that have successfully produced these effects will be reviewed, and several recently reported ESA systems will be introduced and discussed

Electrically Small, Broadside Radiating Huygens Source Antenna Augmented with Internal Non-Foster Elements to Increase Its Bandwidth

© 2002-2011 IEEE. A broadside radiating, linearly polarized, electrically small Huygens source antenna system that has a large impedance bandwidth is reported. The bandwidth performance is facilitated by embedding non-Foster components into the near-field resonant parasitic elements of this metamaterial-inspired antenna. High-quality and stable radiation performance characteristics are achieved over the entire operational bandwidth. When the ideal non-Foster components are introduced, the simulated impedance bandwidth witnesses approximately a 17-fold enhancement over the passive case. Within this-10-dB bandwidth, its maximum realized gain, radiation efficiency, and front-To-back ratio (FTBR) are, respectively, 4.00 dB, 88%, and 26.95 dB. When the anticipated actual negative impedance convertor circuits are incorporated, the impedance bandwidth still sustains more than a 10-fold enhancement. The peak realized gain, radiation efficiency, and FTBR values are, respectively, 3.74 dB, 80%, and 28.01 dB, which are very comparable to the ideal values

A 28-GHz, multi-layered, circularly polarized, electrically small, Huygens source antenna

© 2017 IEEE. A 28 GHz, multi-layered, circularly-polarized (CP), Huygens source electrically small antenna (ESA) is presented. The CP radiation is realized by integrating two orthogonal linearly polarized Huygens source EASs into one with an asymmetrical arc strip feed providing the necessary 90° phase difference. Finally, the CP Huygens source ESA exhibits the properties: ka = 0.942; 1.41% FBW-10dB with a 0.47% 3-dB axial ratio (AR) fractional bandwidth; and peak realized gain, FTBR, and radiation efficiency values are 2.03 dBi, 26.72 dB, and 73.4%, respectively. To confirm its efficacy for on-body applications, the specific absorption rate (SAR) values of the Huygens source ESA is evaluated and found to be very low

Electrically Small, Low-Profile, Huygens Circularly Polarized Antenna

© 1963-2012 IEEE. The design, simulation studies, and experimental verification of an electrically small, low-profile, broadside-radiating Huygens circularly polarized (HCP) antenna are reported. To realize its unique circular polarization cardioid-shaped radiation characteristics in a compact structure, two pairs of the metamaterial-inspired near-field resonant parasitic elements, the Egyptian axe dipole (EAD) and the capacitively loaded loop (CLL), are integrated into a crossed-dipole configuration. The EAD (CLL) elements act as the orthogonal electric dipole (magnetic dipole) radiators. Balanced broadside-radiated electric and magnetic field amplitudes with the requisite 90° phase difference between them are realized by exciting these two pairs of electric and magnetic dipoles with a specially designed, unbalanced crossed-dipole structure. The electrically small (ka = 0.73) design operates at 1575 MHz. It is low profile 0.04λ0, and its entire volume is only 0.0018λ03. A prototype of this optimized HCP antenna system was fabricated, assembled, and tested. The measured results are in good agreement with their simulated values. They demonstrate that the prototype HCP antenna resonates at 1584 MHz with a 0.6 dB axial ratio, and produces the predicted Huygens cardioid-shaped radiation patterns. The measured peak realized LHCP gain was 2.7 dBic, and the associated front-to-back ratio was 17.7 dB

Electrically Small, Low-Profile, Planar, Huygens Dipole Antenna with Quad-Polarization Diversity

© 1963-2012 IEEE. An electrically small, low profile, planar, Huygens dipole antenna with four reconfigurable polarization states is presented. The design incorporates both electric and magnetic near-field resonant parasitic elements and a reconfigurable driven element. The four polarization states include two orthogonal linear polarized (LP) and two circular polarization (LHCP and RHCP) states. A 1.5 GHz prototype was fabricated (partially with 3-D additive manufacturing), assembled, and tested. The measured results, in good agreement with their simulated values, demonstrate that even with its simple configuration, electrically small size (ka =0.944), and low-profile height (0.0449 λ0), this reconfigurable Huygens antenna possesses stable broadside radiation performance in all of its four polarization states. The measured results demonstrate that in its x(y)-LP state, the peak realized gain, front-to-back ratio, and radiation efficiency values are, respectively, 3303 dBi (2.97 dBi), 10.7 dB (9.9 dB), and 68.2% (67.5%). For the LHCP (RHCP) states, they are, respectively, 2.82 dBi (2.74 dBi), 11.4 dB (12.5 dB), and 67.1% (65.9%)

Electrically small metamaterial-inspired antennas with active near field resonant parasitic elements: From theory to practice

© 2017 Euraap. By augmenting several classes of metamaterial-inspired near-field resonant parasitic (NFRP) electrically small antennas (ESAs) with active (non-Foster) circuits, we have achieved performance characteristics surpassing their fundamental passive bounds. The designs not only have high radiation efficiencies, but they also exhibit large frequency bandwidths, large beam widths, large front-to-back ratios, and high directivities. Furthermore, the various initially theoretical and simulated designs have led to practical realizations. These active NFRP ESAs will be reviewed and recently reported designs will be introduced and discussed