Front-to-back ratio

About: Front-to-back ratio is a research topic. Over the lifetime, 292 publications have been published within this topic receiving 3314 citations.

Triangular Lattice Dielectric EBG Antenna

Abstract: A novel electromagnetic band-gap (EBG) antenna based on a triangular lattice of dielectric rods is presented and analyzed using an in-house developed finite-difference-time-domain software simulator. The design steps and the simulations results are presented, focusing on the design of antenna structures with high directivity patterns on the H-plane. Finally, the measurement results of a set of experiments carried out on a prototype designed and built to operate in the X-band are presented and discussed, showing very good agreement with simulations: 31% fractional bandwidth and an average gain of 11.5 dBi are achieved within the bandwidth with 27 dB front-to-back-ratio in the azimuthal plane.

A wearable antenna based on fabric materials with circular polarization for Body-centric wireless communications

Abstract: A compact and simple structure antenna for wearable application at 2.4 GHz is presented and studied. The felt fabric material is used in this paper due to its suitable thickness and dielectric constant. This material provides high flexibility which can be easily worn on a body and incorporated into our daily clothes. In view of the fact that the design will work on a moving person, therefore a circularly polarized antenna is desired to optimize the off-body communication link. The Cicular Polarization (CP) is achieved by introducing truncated corners on the patch. The antenna size is 60 × 60 × 2 mm 3 . The Axial Ratio (AR), the Front to Back Ratio (FRB) and the realized gain are 0.96 dB, 10.5 dB, and 4.62 dB, respectively indicating a good performance of the antenna at the desired frequency. Furthermore, the antenna was investigated when operating near the body. The obtained result shows that the design has performance similar to the case of free space. This is due to the present of the full ground plane that acts as a shielding between the antenna and body. Finally, the Specific Absorption Rate (SAR) is carried out and showed that the antenna has a level less than the limits fixed by the FCC standard. Therefore, the antenna could be useful for wearable applications.

Tunable Terahertz Filter-Integrated Quasi-Yagi Antenna Based on Graphene

Abstract: In this paper, a filter-integrated quasi-Yagi antenna (FIQYA) with quasi-independently tunable passband and front-to-back ratio is proposed by using graphene. The graphene at two ends of the coupled-line ring resonator mainly affects the impedance bandwidth while the front-to-back ratio of radiation patterns is attributed to the graphene-implanted open-circuited director. The bandwidth and front-to-back ratio tunability is accomplished by altering the complex conductivity of graphene controlled by chemical potential. For verification, a 2-THz FIQYA using both perfect electric conductor (PEC) and graphene with two different controllable chemical potentials (μ c1 and μ c2) is simulated. The simulated results show that the maximum tunable impedance bandwidth of the FIQYA is varied from 186 to 235 GHz without affecting the radiation patterns when μ c1 changes from 0 to 0.2 eV. The maximum tunable front-to-back ratio is changed from 11.7 to 15.4 dB while μ c2 is altering from 0 to 0.6 eV, maintaining an acceptable matching bandwidth in all cases.

Near-zero-refractive-index metasurface antenna with bandwidth, directivity and front-to-back radiation ratio enhancement

Abstract: In this paper, a novel metasurface-based Fabry–Perot Cavity antenna is presented The antenna is wideband, directive and has a high front-to-back ratio The idea of the antenna is based on loading

Substrate integrated waveguide cavity backed slot antenna with parasitic slots for dual-frequency and broadband application

Abstract: In this paper, a novel design of substrate integrated waveguide (SIW) cavity backed slot antenna for dual frequency and broadband application is demonstrated. In the proposed design, a parasitic slot is placed along with the conventional central slot at the top metallic plate of the cavity to generate dual frequency resonances at 10.08 GHz and 11.96 GHz. The central slot is placed at the center of the cavity and it is excited by TE 120 mode of the cavity to radiate into free space. However, the placement of parasitic slot in the cavity modifies the surface current distribution at top metallic plate at higher frequency and as a result, a hybrid mode resonance is achieved. Both these resonances contribute to the dual frequency operation of the antenna with unidirectional radiation pattern, high gain, high front-to-back ratio (FTBR) at both operating frequencies. The proposed antenna achieves a bandwidth of 108 MHz (1%) and 100 MHz (0.83%), a gain of 5.5 dBi and 5.3 dBi and front to back ratio of 10 dB and 12 dB respectively at first and second resonant frequency. The slot lengths can be varied to achieve a frequency ratio of two resonant frequencies in a broad range of 1.18–1.5. The length of the slot pair can also be tuned to merge the dual resonances to achieve a broadband response. A design example of broadband antenna is also demonstrated. The proposed design shows a bandwidth of 380 MHz (3.6%), a gain of 5.2–5.8 dBi and FTBR of 15 dB throughout the operating bandwidth.