Design of the small microstrip antenna based on the WLAN/UWB wireless communication system

The antenna,as the component of receiving and sending signals in the front end of the wireless communication system,plays an important role in the communication quality,and is often the main obstacle to the development of the miniaturization of the wireless communication system.The microstrip antenna is composed of a metal radiation patch which can be pasted on the dielectric substrate.The choice of the shape of the metal patch can be arbitrary.The conventional shape is usually chosen as the metal patch to simplify the analysis and prediction of its performance.The dielectric constant of the microstrip antenna substrate is relatively low in order to enhance the field intensity of the edge radiation field.However,the dielectric constant of the substrate needs to be greater than 5 in order to meet the needs of other performance of the microstrip antenna,so that the radiation edge effect cannot be enhanced,resulting in the greater contradictions.

Textile UWB 5G Antenna for Human Blood Clot Measurement

The antenna plays an essential role in the medical industry.The short-range 5th Generation(5G)communication can be used for seamless transmission,reception,patient monitoring,sensing and measuring various processes at high speeds.A passive Ultra Wide Band(UWB)antenna,used as a sensor in the mea-surement of Prothrombin Time(PT)i.e.,blood clot is being proposed.The inves-tigated micro-strip patch UWB antenna operating in the frequency range of 3.1 to 10.6 GHz consists of a circular patch with a diamond-shaped slot made of jeans substrate material with good sensing properties is accomplished by adjusting the copper thickness of the patch.Due to the turbidity in blood plasma,PT measure-ment is the repetitive approach to get accurate value.In order to solve this issue,an antenna is designed,fabricated and analysed to obtain the accurate PT mea-surements from blood plasma.The blood clotting is observed by electromagnetic emitted voltage converted into the frequency range of 5 to 10 GHz and voltage range of 0.66 to 0.87 mV.The circular UWB antenna is constructed employing jean’s substrate with a partial ground plane to improve the S-parameter,gain,bandwidth and performance characteristics.The proposed antenna with Specific Absorption Rate(SAR)value within the acceptable range can be used as a wear-able device in the human body,leveraging 5G technology.This antenna is well suited for various other applications like wireless sensors,wearable devices and short-range communication applications.

Golay Sequence Based Time-Domain Compensation of Frequency-Dependent I/Q Imbalance

A time-domain frequencydependent I/Q imbalance compensation scheme based on Golay complementary sequence for receiver is presented. By utilizing property of Golay sequence, the signal and its conjugate interference(image interference)in preamble are separated by correlation and used to estimate I/Q imbalance parameters.After that, a Least Square(LS) estimation of compensation filter is obtained and adopted in the compensation structure. Two applications of the presented algorithm are discussed: we could either estimate the channel along with I/Q imbalance or estimate the imbalance parameter only to maintain a lower cost. Both applications are testified by simulation. The results show that the image interference is significantly suppressed even in poor SNR condition, and the computation cost of the algorithms is low.

New band-notched UWB antenna

A simple and compact ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.

A NOVEL ULTRA WIDEBAND MONOPOLE ANTENNA WITH BAND-NOTCHED CHARACTERISTICS

A simple and compact microstrip-fed Ultra WideBand(UWB) printed monopole antenna with band-notched characteristic is proposed in this paper.The antenna is composed of a square ring with a small strip bar,so that the antenna occupies about 7.69 GHz bandwidth covering 3.11～10.8 GHz with expected band rejection from 5.12 GHz to 5.87 GHz.A quasi-omnidirectional and quasi-sym-metrical radiation pattern is also obtained.This kind of band-notched UWB antenna requires no ex-ternal filters and thus greatly simplifies the system design of UWB wireless communication.

Experimental Study of On-Body Radio Channel Performance of a Compact Ultra Wideband Antenna

In this paper, on-body radio channel performance of a compact ultra wideband (UWB) antenna is investigated for body-centric wireless communications. Measurement campaigns were first done in the chamber and then repeated in an indoor environment for comparison. The path loss parameter for eight different on-body radio channels has been characterized and analyzed. In addition, the path loss was modeled as a function of distance for 34 different receiver locations for propagation along the front part of the body. Results and analysis show that, compared with anechoic chamber, a reduction of 16.34% path loss exponent is noticed in indoor environment. The antenna shows very good on-body radio channel performance and will be a suitable candidate for future efficient and reliable body-centric wireless communications.

Pulse Generation and Compression Techniques for Microwave Electronics and Ultrafast Systems

Ultrabroadband systems and ultrafast electronics require the generation,transmission,and processing of high-quality ultrashort pulses rang-ing from nanoseconds(ns)to picoseconds(ps),which include well-established and emerging applications of time-domain reflectometry,arbitrary wave-form generation,sampling oscilloscopes,frequency synthesis,through-wall radar imaging,indoor communication,radar surveillance,and medical radar detection.Impulse radar advancements in industrial,scientific,and medical(ISM)domains are,for example,driven by ns-scale-defined ultrawideband(UWB)technologies.Nevertheless,the generation of ultrashort ps-scale pulses is highly desired to achieve unprecedented performances in all these ap-plications and future systems.However,due to the variety and applicability of different pulse generation and compression techniques,the selection of optimum or appropriate pulse generators and compressors is difficult for practitioners and users.To this end,this article aims to provide a comprehen-sive overview of ultrashort ns and ps pulse generation and compression techniques.The proposed and developed pulse generators available in the litera-ture and on the market,which are characterized by their corresponding pros and cons,are also explored.The theoretical analysis of pulse generation us-ing a nonlinear transmission line(NLTL)presented in the literature is briefly explained as well.Additionally,a holistic overview of these pulse genera-tors from the perspective of applications is given to describe their utilization in practical systems.All of these techniques are well summarized and com-pared in terms of fundamental pulse parameters,and research gaps in specified areas are highlighted.A thorough discussion of previous research work on various topologies and techniques is presented,and potential future directions for technical advancement are examined.