Shanshan Gao

A Compact UWB Bandpass Filter with Wide Stopband

A compact ultra-wideband (UWB) bandpass filter is presented by using a modified stepped impedance resonator (SIR) and defected ground structures (DGSs). The modified SIR is to generate multiple-resonant peaks within the UWB passband and tighten the coupling with the feed-lines. Then, the DGSs are to enhance the coupling degree of coupled lines and realize wide stopband. From simulated and measured results, the filter shows good UWB performance, including low insertion loss within the passband, a small group delay variation, and a wide stopband with −20 dB attenuation up to 19.6 GHz.

Compact Ultra-Wideband (UWB) Bandpass Filter Using Modified Stepped Impedance Resonator

A novel ultra-wideband (UWB) bandpass filter is proposed by using a modified stepped impedance resonator (SIR). The modified SIR can generate multiple-resonant peaks within the UWB passband and the feed-lines at the two sides can enhance coupling degree. The proposed filter shows good UWB passband performance with low return loss and flat group delay variation in both simulated and measured results. It has a simple and compact structure.

2.45 GHz Body-Worn Planar Monopole Antenna and its application in Body-Worn Mimo System

In this paper, a body-worn planar monopole antenna is proposed for body-centric wireless communications systems (BWCS) working at the frequency around 2.45 GHz. The effect of human body in the near vicinity of the antenna on the antenna performance is also investigated. Based on the body-worn monopole antenna, a simple body-worn MIMO system is developed to improve the capacity of BWCS. The effect of mutual coupling between elements on capacity is also considered. The studies show that the capacity of data transmission is improved when MIMO system is adopted.

Wideband antenna for ultra-wideband (UWB) body-centric wireless communications

Recently, wearable wireless communication system has attracted much attention. It is used widely in the areas of military operations, medical field and personal communication applications. With the rapid development of the wearable systems, wearable antennas are facing with a considerable design challenge, especially in the bandwidth of the antenna. This paper proposed a wearable antenna for ultra-wideband (UWB) communication systems. The antenna is composed of a quasi-trapeziform ground and a rectangular patch with two symmetrical bevel slots at each side of the lower edge of the patch. The two bevel slots on the patch can enhance the bandwidth of the antenna to satisfy the requirements of UWB communication systems. And the size of the quasi-trapeziform ground can influence the match of the antenna. The antenna shows UWB bandwidth with high performance. Then, we study the performance of the antenna worn on body. It also shows good performance. Simulation was accomplished using Ansoft HFSS and CST Microwave Studio, both simulated results are presented and they are in good agreement.

Compact UWB Bandpass Filter with a Notched Band

A compact wideband bandpass filter with a notched band is proposed, designed and implemented for ultra-wideband (UWB) system application on the basis of a modified stepped impedance resonator and asymmetrical interdigital feed-lines structures. The modified stepped impedance resonator can not only generate multiple-resonant peaks within the UWB passband but also easily realize a tight coupling with the feed-lines to realize a wide passband. The asymmetrical interdigital feed-lines can generate a notched band at 5.98 GHz with no significant influence on the passband performances. Both simulated and measured results are presented and they are in good agreement.

Wideband antenna and wideband bandpass filter for wearable systems

With the rapid development in wearable systems in recent years, the need for wireless communication components integrated into clothing is increasing. Wearable antennas and radio frequency (RF) devices are faced with a considerable design challenge, especially in the gains of antennas and performances of filters. This paper presents a wearable antenna and a wearable bandpass filter for ultra-wideband (UWB) communication systems. The antenna is composed of a cone-shaped patch, a coplanar waveguide (CPW) ground, and several uniform semi-ring slots. The slots can improve the gain of the antenna and had no significant effect on the bandwidth. The filter is constituted of a modified stepped impedance resonator (SIR), two identical feed-lines, and a CPW ground. Simulation was accomplished using Ansoft HFSS and CST Microwave Studio, both simulated results are presented and they are in good agreement.

Ultra wide-band slot antenna based on liquid crystal polymer material for millimeter wave application

A millimeter wave ultra-wide band (UWB) tapered slot antenna is presented based on a multilayer liquid crystal polymer (LCP) circuit process. The multilayer circuit board consists of eight copper layers and seven LCP layers. In order to enhancing the bandwidth, two overlapped tapered slots with different flare angle are applied in the 3rd and the 5th copper layers, respectively. A low backward radiation characteristic is achieved due to using the ground-backed structure. A simple design guideline is detected and the dimension is optimized. The designed results indicate that the millimeter wave UWB slot antenna can work in the frequency band of 33GHz-60GHz (a relative bandwidth of 58%). The radiation patterns are calculated at three typical frequencies and the analysis demonstrates that an elliptical polarization performance is obtained within the total operation frequency band. The study also demonstrates that the LCP process is suitable for developing lightweight and high performance millimeter wave antennas.