A novel technique to improve gain in transparent UWB antennas

A novel technique to improve the performance of AgHT-8 transparent polymer antennas is proposed in this paper. A spit-ring resonator is introduced on the radiating patch to enhance gain. The resonator basically concentrates the radiating energy to the central area of the patch thus improving gain. The designed antenna demonstrates good gain while maintaining the original transparency of the material. Such an antenna inscribed on the commercially available AgHT-8 sun shielding film material makes it a viable option for wireless applications like in-house base stations and applications requiring fast data rate transfers which can be mounted on windows and glass panels. © 2011 IEEE.Solutia Inc., St. Louis, Missouri, US

A non-thermal soldering technique to improve polymer based antenna performance

Copyright @ 2010 EuMCA non-thermal soldering technique using cold solder or electrically conductive epoxy for connecting SMA connectors to polymer based antennas is proposed in this paper. The proposed technique prevents damage to the polymer due to the solder iron heat and also the loss of efficiency through the use of indirect connections of the coaxial feed via copper pads glued to the antenna. The direct connection of the feed points via SMA connectors on to a transparent antenna designed on AgHT-8 material has been demonstrated. The method can also be applied to solder the coaxial feed points directly to the antenna instead of using copper pads which will introduce additional reflection losses. The technique involves the use of colder soldering instead of hot soldering so as to not damage the polymer based antenna as well as improve the efficiency of the antenna

A novel technique and soldering method to improve performance of transparent polymer antennas

This article is archived here with permission from IEEE - Copyright @ 2010 IEEEA novel technique and a non-thermal soldering method to improve the performance of AgHT-8 transparent polymer antennas are proposed in this paper. The proposed technique involves the removal of the coating layer at areas on the CPW ground and feed line where the connectors of the coaxial feed or legs of the SMA connectors will be attached, and applying a coat of silver paint on the exposed areas before cold soldering the coaxial connections or SMA connector legs. The non-thermal or cold soldering using electrically conductive paste enables direct soldering of the co-axial feed points or connector legs which cannot otherwise be done with hot or thermal soldering. This type of connection greatly enhances the performance of the AgHT-8 polymer antennas compared to coaxial feed point connections through hot soldered copper pads glued to the surface of the polymer coating. The proposed technique also gives a stronger connection bond than directly cold soldering the feed points or connectors to the smooth surface of the AgHT-8 material. Furthermore, the copper pad connection technique also introduces additional losses contributed by the adhesive properties of the glue used. This proposed novel technique and soldering method may be extended to enhance antenna performance made from other similar transparent conductive polymers like IT

Investigative study on the development of a green UWB antenna

Copyright @ 2010 ISA

Pilot-Symbol-Aided 16PSK and 16QAM for Digital Land Mobile Radio Systems

The paper proposes a novel pilot-symbol-aided (PSA) technique for fading compensation of digital signals in the mobile environments. In a PSA system, the data sequence at the transmitter is divided into frames of data. A pilot symbol from a known pseudoradom-symbol sequence is inserted periodically into a frame of data symbol for transmission. In a conventional PSA-receiver, these pilot symbols are extracted from the received signal and used to estimate the effects of signal distortion introduced in the fading channel. The resultant estimates are then used to correct the distortion effects in the received data frames. In the paper, a novel estimation technique that uses the data symbols as well as the pilot symbols is proposed. The technique has the major advantages of simple implementation and short storage-delay time. Results are presented in a series of computer-simulation tests. These assess the effectiveness of the estimation technique on the BER performances of a 16-ary phase-shift keyed (16PSK) and a 16-ary quadrature-amplitude modulated (16QAM) signals in the frequency-selective and frequency-nonselective Rayleigh fading channels. The channels are corrupted by co-channel interference or additive white Gaussian noise. Results of differential-detected 16PSK and star-16QAM signals are also presented for comparison. It has been shown that, the use of PSA technique can significantly improve the bit-error-rate performances of the systems, relative to those using differential detection.postprin

Performance of a pilot symbol-aided technique in frequency-selective Rayleigh fading channels corrupted by co-channel interference and Gaussian noise

The paper studies the effects of a pilot symbol-aided (PSA) technique on the performances of 16QAM and 16PSK in the frequency-selective Rayleigh fading channels corrupted by co-channel interference and Gaussian noise. The PSA technique employs both the pilot symbols and data symbols for fading estimation. Computer simulation results have shown that significant improvements on bit-error rate performances of the signals can be achieved through the use of the PSA technique.published_or_final_versio

Combining PSA fading estimation techniques for TCM and diversity reception in Rician fading channels

In this paper, a novel pilot-symbol-aided (PSA) technique is proposed for fading estimation in the land mobile satellite fading channels. The proposed technique combines the fading estimates obtained from a bandwidth-efficient technique and a conventional technique according to the signal-to-noise ratios (SNRs) of the fading estimates. To enhance the transmission quality, trellis-coded modulation (TCM) and diversity reception are employed in the system, and the combined estimates are subsequently used to correct the channel fading effects, to weight the signals from different diversity branches, and to provide channel state information of the Viterbi decoder. Monte Carlo computer simulation has been used to study the bit-error-rate (BER) performance of the proposed technique on trellis-coded 16-ary quadrature amplitude modulation in the frequency non-selective Rician fading channels. Results have shown that the proposed PSA technique requires a very low bandwidth redundancy to provide satisfactory BER performance at low SNRs, and thus is suitable for use with TCM and diversity reception to achieve both bandwidth and power-efficient transmission.postprin

Data-aided fading estimation technique for shadowed mobile satellite fading channels

A novel data-aided fading estimation technique that employs both pilot and data symbols is proposed to significantly reduce the bandwidth redundancy of the pilot-symbol-aided (PSA) systems using receivers with low complexity and latency in the shadowed mobile satellite fading channels. The shadowed mobile satellite fading channels are modeled as the sum of a lognormally distributed direct component and a Rayleigh distributed multipath component, and the PSA system employs 16-ary quadrature-amplitude-modulation (16QAM) for transmission. Monte Carlo computer simulation has been used to assess the technique on the bit-error-rate (BER) performances of the system in the light shadowed, the average shadowed and the heavy shadowed Rician fading environments. The results have shown that the proposed technique requires a very low bandwidth redundancy to provide satisfactory BER performances, and can substantially lower the error floors of the PSA systems.postprin

Performance of 16-ary DEQAM signalling with a pre-rotated constellation through nonlinear satellite channels.

The effects of AM-AM and/or AM-PM conversions of a high-power amplifier (HPA) on the performance of a bandlimited 16-ary differentially encoded quadrature amplitude modulated (16-ary DEQAM) system are investigated in the presence of additive white Gaussian noise. The results obtained by computer simulation show that a combination of moderate output backoff from saturation of the HPA and prerotation of the transmitted signal constellation can considerably improve the system performance. The performance of the proposed system is compared to that of a 16-ary DEQAM system using an RF predistorter. The results show that the degradation due to the AM-AM and AM-PM conversion effects of the HPA tested is much less than that of the sum of the degradations caused by the individual AM-AM and AM-PM conversion effects. Also, the AM-AM signal distortion causes more degradation than does the AM-PM signal distortion, under the same assumed conditions. With prerotation and moderate output backoff values of the HPA, the AM-PM distortion in the received signal-space vectors can nearly be eliminated.published_or_final_versio

Bandwidth-efficient pilot symbol aided technique for trellis-coded modulation in land mobile satellite fading channels

A bandwidth-efficient pilot-symbol-aided technique is proposed for use with trellis-coded modulation (TCM). Computer simulation has been used to assess the effects of the technique on the bit error rate (BER) performances of trellis-coded 16-ary quadrature amplitude modulation (TC-16QAM) in the flat Rician and shadowed Rician fading channels corrupted with additive white Gaussian noise. The results have shown that the proposed technique needs a very low bandwidth redundancy and can work effectively at low signal-to-noise ratios, so it is suitable for use with TCM.published_or_final_versionThe IEEE Conference on Wireless Communications and Networking (WCNC 1999), New Orleans, LA., 21-24 September 1999. In IEEE Wireless Communications and Networking Conference Proceedings, 1999, v. 1, p. 183-18