Determination and Analysis of the Optical Parameters of Polymer Thin Film based on Spectrum

A method to determine the optical parameters of polymer thin film by use of the transmission spectrum is proposed, with the improved simulated annealing algorithm developed to perform its inverse calculation. A special phenomenon due to the almost equal refractive index between film and substrate, that is, the small waves on spectrum curves which make the information of film thickness losing, has been discussed in detail. Based on the tested transmission spectrums of polymer optical thin films fabricated on K9 glass substrates, the dispersion curve of refractive index in visible band is figured out. Its calculated refractive index in the wavelength of 1547 nm is 1.3933, with the accuracy higher than 0.58% by comparing with the one measured by traditional coupled prism method. The analyzed result shows that the improved algorithm works well, by which the calculated optical parameters can converge to the right values

The microstrip antenna with PBG used for 3G system

Aiming at the request of the antenna used for 3G system, we first analyze the characteristics of microstrip antenna and design methods of size structure, and then design the microstrip antenna with PBG by using MWO. The detailed analysis inquiries into the influence on the reflection coefficient S-11 by key parameters, such as the length of PBG sides, the structural periodicity of PBG, the feeding point of antenna, the dielectric constant and thickness of circuit board have been studied. Finally, the design principles and advantages of the microstrip antenna with PBG are summarized

A Novel Printed Folded Dipole Antenna Used for Modem RFID System

For the minimization of RFID tag antenna, we designed a printed folded dipole antenna working at 2.4 GHz. And a mirror compensation technology was introduced to improve the radiation feature of antenna with better return loss characteristic and directivity. The simulated results show that when VSWR (Vertical Standing Wave Ratio) is less than 2, the antenna bandwidth is up to 0.39 GHz absolutely and to 15.48% relatively. Considering engineering processes, the influences of dielectric constant epsilon(r), board thickness, folding degree and other parameters on the properties of this antenna are particularly studied. On the basis, a dual-frequency folded dipole antenna is proposed, which can work in two main frequency for RFED system, i.e. 915 MHz and 2.4 GHz. Moreover, an antenna sample made on this novel structure has been tested and the results show that the bandwidth of antenna is improved in further, along with hemisphere directional radiation characteristics

The application of PBG configuration in planar spiral antenna

For the requirement of 3G mobile terminal at present, we have designed a new kind of WCDMA mobile terminal spiral antenna with PBG structure, which is capable of working in 1920-2170 MHz frequency broad band. Applying PBG configuration in planar spiral antenna, the characteristics is improved significantly and the size is also reduced. It makes the band width reach 250 MHz, which covers the whole emitting and receiving frequency band of WCDMA system. This antenna has been simulated and designed by using simulation design software, and the experiment results are agree well with the simulation results, which show that the varied period configuration of PBG is more benefit to improve antenna performance

A Novel Ceramic Fractal Antenna for Modern RFID System

A novel double bands ceramic fractal antenna working at 2.4 GHz and 5.8 GHz is designed for the minimization requirement of RFID tag antenna. The simulated results show that when VSWR (Vertical Standing Wave Ratio) is less than 2, the antenna absolute bandwidths are up to 0.39 GHz and 1.85 GHz in 2.4 GHz and 5.8 GHz respectively, with relative bandwidths up to 15.20% and 35.82% respectively,. Considering engineering processes, the influence of dielectric constant F, and substrate thickness are studied in detail. At last we proposed an optimized antenna with duel fractal structure, which can cover all primary frequency bands of RFID system, from 2.17 GHz to 7.05 GHz

A Ceramic Spiral Antenna used for Modern RFID System

For the requirements of wideband RFID antenna, we designed a ceramic spiral antenna working at 915 MHz. The simulated results show that when VSWR (Vertical Standing Wave Ratio) is less than 2, the antenna bandwidth is up to 1.22 GHz (0.57 similar to 1.79 GHz) absolutely and to 133.21% relatively at the central frequency of 0.9 GHz. Considering engineering processes, the influence of dielectric constant epsilon(r) and thickness of circuit board are particularly studied. On this basis, a dual-frequency ceramic spiral antenna is proposed, which can work with respect to all the main frequencies of RFID system, i.e. 915 MHz and 2.4 GHz

Development of composite plate for microwave antenna

Conference Name:2011 International Symposium on Advanced Packaging Materials, APM 2011. Conference Address: Xiamen, China. Time:October 25, 2011 - October 28, 2011.A new kind of machinable composite plate was developed for microwave antenna in this paper, in which ceramic powder of CaO-Li2O-Ln 2O3-TiO2 was mixed with PTFE polymer in different proportions. It was showed that the permittivity of the composite plate was enhanced from 4 to 15 with the increasing content of ceramic powder; meanwhile, the quality factor was maintained at 1000GHz. The antenna was obtained with the composite plate which was machined to suitable size and covered with copper electrodes. The antenna's bandwidth was about 60MHz and standing wave ratio was near 1.12. ? 2011 IEEE

Complementary Multi-Band Dual Polarization Conversion Metasurface and Its RCS Reduction Application

In this paper, we present a metasurface composed of complementary units that can realize orthogonal linear and linear-to-circular polarization conversion in multi-band. Linear polarization conversion has seven high-conversion frequency bands: 9.1–9.7 GHz, 15.6–17.6 GHz, 19.4–19.7 GHz, 21.2–23.1 GHz, 23.5–23.8 GHz, 26.2 GHz, and 27.9 GHz. Linear-to-circular polarization conversion also has seven frequency bands with axial ratios (ARs) less than 3 dB: 8.9–9.0 GHz, 9.9–14.7 GHz, 19.1–19.3 GHz, 23.2–23.35 GHz, 23.4 GHz, 24.1–25.4 GHz, and 27.2–27.8 GHz, with the generation of multiple bands extended by the combination of complementary units. Then, we utilize the combined polarization conversion unit’s mirror placement to form a 4 × 4 array to realize the phase difference cancellation of the reflective field, giving the metasurface the radar cross section (RCS) reduction function and the dual-band 10-dB monostatic RCS reduction bandwidth: 8.9–9.7 GHz and 15.5–26.1 GHz. The measured and simulated results were essentially identical. Because the design uses the complementary units to form an array to expand the polarization conversion frequency bands, it provides a novel idea for future designs and can be applied to multiple microwave frequency bands

Complementary Multi-Band Dual Polarization Conversion Metasurface and Its RCS Reduction Application

In this paper, we present a metasurface composed of complementary units that can realize orthogonal linear and linear-to-circular polarization conversion in multi-band. Linear polarization conversion has seven high-conversion frequency bands: 9.1–9.7 GHz, 15.6–17.6 GHz, 19.4–19.7 GHz, 21.2–23.1 GHz, 23.5–23.8 GHz, 26.2 GHz, and 27.9 GHz. Linear-to-circular polarization conversion also has seven frequency bands with axial ratios (ARs) less than 3 dB: 8.9–9.0 GHz, 9.9–14.7 GHz, 19.1–19.3 GHz, 23.2–23.35 GHz, 23.4 GHz, 24.1–25.4 GHz, and 27.2–27.8 GHz, with the generation of multiple bands extended by the combination of complementary units. Then, we utilize the combined polarization conversion unit’s mirror placement to form a 4 × 4 array to realize the phase difference cancellation of the reflective field, giving the metasurface the radar cross section (RCS) reduction function and the dual-band 10-dB monostatic RCS reduction bandwidth: 8.9–9.7 GHz and 15.5–26.1 GHz. The measured and simulated results were essentially identical. Because the design uses the complementary units to form an array to expand the polarization conversion frequency bands, it provides a novel idea for future designs and can be applied to multiple microwave frequency bands