A Curved Microstrip Patch Antenna Designed From Transparent Conductive Films

Transparent microstrip patch antennas suffer from low radiation efficiency and gain when manufactured using transparent conductive films (TCFs), mainly at low frequency (starting from the microwave S band). To address this problem, we propose a curved microstrip patch antenna designed using transparent materials. This new configuration has proven to be a simple and effective solution to improve the radiation efficiency and gain of TCF printed antennas. In fact, when typical values of the TCF surface resistance are considered (between 2 and 10 Ω/sq), the new antenna features a radiation efficiency of up to 72.3% and a realized gain of up to 5.3 dBi at 2.15 GHz, with a significant improvement in comparison with the flat transparent microstrip antenna (up to 17.7% radiation efficiency, and 0.5 dBi realized gain). Good transparency and lightweight is ensured by the deposition of the TCF on a polyethylene terephthalate film, which lies, in turn, on a 3D-printed curved polyethylene terephthalate glycol supporting frame. Simulations using Ansys HFSS are presented to demonstrate the potential of the proposed configuration. Then, a prototype of the transparent curved patch antenna is fabricated and measured to assess the simulated results

A Transparent Curved Microstrip Patch Antenna

Microstrip antennas fabricated using transparent conductive oxides suffer from low efficiency and gain in the S band and lower. We propose here a modified version of the curved microstrip patch antenna, which has been designed with transparent materials. In this paper, we will show how this configuration is able to improve the radiation efficiency and gain of transparent microstrip antennas

Vibrational properties of mixed Y3Al5O12)x-(Y3Sc2Ga3O12)1-x crystals

The vibrational properties of yttrium aluminum garnet (YAG), yttrium scandium gallium garnet (YSGG), and mixed (YAG)(x) - (YSGG)(1-x) structures (0 < x < 1) were investigated by means of Raman spectroscopy. By comparison with the vibrational spectrum of the YAG structure, the attribution of the Raman modes of the YSGG is proposed. The spectra were analyzed with a model of isolated polyhedra and the formation of mixed structures was verified. The Raman modes in the mixed structures lie between those of the pure garnets indicating the presence of truly mixed and not separated phases. An analytical model based on the free tetrahedral approximation to study the position of the vibration frequencies as a function of the relative concentration of the garnets is proposed and applied to the study of the A(1g) breathing mode at 785 cm(-1) in the pure YAG structure and downshifted at 752 cm(-1) in the pure YSGG structure. The proposed analysis allows to verify both the quality of the grown crystal and to assess the relative concentration of the garnets. (c) 2006 American Institute of Physics

Compositional tuning of photoluminescence properties in Nd-doped YAG-YSGG mixed structures

The photoluminescence (PL) properties of neodymium-doped yttrium aluminum garnet and yttrium scandium gallium garnet mixed structures were investigated as a function of the relative concentration of the two garnets. The blue shift of the emission bands in the 930-950-nm range is ascribed to compositional tuning effect. An analytical model to estimate the variation of the PL position as a function of the compositional host structure is proposed