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.

Via-less electromagnetic band-gap-enabled antenna based on textile material for wearable applications.

Abstract: A compact fabric antenna structure integrated with electromagnetic bandgap structures (EBGs) covering the desired frequency spectrum between 2.36 GHz and 2.40 GHz for Medical Body-Area Networks (MBANs), is introduced. The needs of flexible system applications, the antenna is preferably low-profile, compact, directive, and robust to the human body's loading effect have to be satisfied. The EBGs are attractive solutions for such requirements and provide efficient performance. In contrast to earlier documented EBG backed antenna designs, the proposed EBG behaved as shielding from the antenna to the human body, reduced the size, and acted as a radiator. The EBGs reduce the frequency detuning due to the human body and decrease the back radiation, improving the antenna efficiency. The proposed antenna system has an overall dimension of 46×46×2.4 mm3. The computed and experimental results achieved a gain of 7.2 dBi, a Front to Back Ratio (FBR) of 12.2 dB, and an efficiency of 74.8%, respectively. The Specific Absorption Rate (SAR) demonstrates a reduction of more than 95% compared to the antenna without EBGs. Moreover, the antenna performance robustness to human body loading and bending is also studied experimentally. Hence, the integrated antenna-EBG is a suitable candidate for many wearable applications, including healthcare devices and related applications.

Microstrip patch back radiation reduction using metamaterial superstrate

Abstract: The capability of the capacitively loaded loop (CLL) metamaterial (MTM) superstrate to attenuate surface waves thereby reducing the back radiation of microstrip patch antennas is examined. To understand the surface wave suppression mechanism, theoretical approaches of a grounded dielectric slab waveguide is provided. Both theoretical and numerical analyses show that the proposed superstrate causes a drastic attenuation of surface wave propagation. To confirm the numerical simulations, the proposed antenna is fabricated and tested. The dimensions of the CLL-MTM covered patch antenna are 0.6λ × 0.8λ × 0.14λ. The radiated gain and efficiency are measured at 7.8 dB and 95%, respectively. Measurements show that the front-to-back ratio is enhanced by more than 12 dB. In comparison with the patch antenna without the CLL-MTM superstrate, the proposed antenna reduces the gain and efficiency by less than 0.1 dB and 2%, respectively.

Antipodal dual exponentially tapered slot antennas (DETSA) with corrugations for front-to-back ratio improvement

Abstract: In this paper, we investigate the effect of edge corrugations on the improvement of the front-to-back ratio (F/B ratio) for the antipodal dual exponentially tapered slot antennas (DETSA). While the inclusion of the corrugation did not have much effect on the peak gain of the antenna, the improvement came mainly from the suppression of the back-lobe levels. A new configuration for the edge corrugation is presented which is capable of improving the front-to-back ratio over the entire UWB band, with an average of 35% improvement over the structure without corrugation. Such improvement was validated by measurement.

Design of Compact Multiband EBG and Effect on Antenna Performance

Abstract: This paper presents the design of Electromagnetic Bandgap (EBG) structure using fractals geometry and its effect on antenna performance. The EBG structure has been designed on substrate єr = 4.3 and thickness h = 1.53 mm. The 1 st iterative EBG structure offers the surface wave attenuation around 20 dB down from 2.94 GHz to 4.58 GHz corresponds to 43.62% bandwidth. The experimental results of 2 nd iterative EBG structure revealed the surface wave attenuation in two bands from 2.45 to 3.36GHz and 8.52 to 11.02 GHz respectively. The surface wave suppression bandwidth for both the bands is 31.325% and 25.59 % respectively. The antenna design with the proposed EBG exhibits improvement in the bandwidth by 3.64%, gain by 3.2 dB and front to back ratio by 15.36 dB in comparison of antenna without EBG. In this paper, an electromagnetic band gap structure design based on fractal geometry is proposed. The proposed design offers the multiple bands and wider bandwidth attenuation in the stopband. This design based on fractal geometry provides the compact EBG structure. The simulated and experimental results have been found in close agreement. The improvement in the antenna performance has also been demonstrated using EBG structure.

Stripline aperture coupled metamaterial mushroom antenna with increased front-to-back ratio

Abstract: The stripline aperture coupling structure is introduced to lower the back radiation of a broadband low-profile metamaterial mushroom antenna. Compared to the feeding structure of a microstrip line aperture coupling, the stripline aperture coupled mushroom antenna exhibits a front-to-back ratio enhancement of 2-14 dB within an operating frequency range of 4.7-6.0 GHz.