Ronghong Jin

Small Ultra-Wideband (UWB) Bandpass Filter With Notched Band

A compact ultra-wideband (UWB) bandpass filter (BPF) with notched band has been proposed and implemented in this letter. H-shaped slot is studied and adopted to tighten the coupling of inter-digital capacitor in order to improve the BPFs performance. Three pairs of tapered defected ground structures (DGS) are formed to assign their transmission zeros towards the out of band signal, thereby suppressing the spurious passband. Combining these two structures we obtain a small sized UWB BPF. Meander line slot is developed to reject the undesired wireless local-area network (WLAN) radio signals. An experimental UWB filter with notched band was fabricated with 35% less length as compared to an embedded open-circuited stub. The measured BPF insertion loss is less than 1.0 dB throughout the pass band of 2.8 to 10.8 GHz, the variation of group delay less than 0.20 ns in this band except for the notched band, and a wide stopband bandwidth with 20 dB attenuation up to at least 20.0 GHz.

Printed Omni-Directional UWB Monopole Antenna With Very Compact Size

A compact rectangular monopole with an equal-width ground plane is presented. This novel structural configuration could significantly improve its radiation performance and decrease its size. The feeding structure composed of a trident-shaped strip and a tapered impedance transformer is presented and discussed. Its impedance bandwidth, defined by measured VSWR less than 2, is from 2.75 to 16.2 GHz with a ratio of about 5.9:1. Both numerical and experimental results show that the proposed monopole antenna has stably omni-directional H-plane radiation patterns with low cross-polarization level within its impedance bandwidth. This novel monopole antenna has ultrawide impedance bandwidth, very compact size (30 mm*8 mm), low fabrication lost, and omni-directional H-plane radiation patterns, which are suitable for various broadband applications.

E-Shape Patch With Wideband and Circular Polarization for Millimeter-Wave Communication

E-shape patch antenna is proposed for millimeter wave frequencies. Using this E-shape structure, the patch antenna is designed for wideband operation at about 31.6-40 GHz for millimeter wave communication. Simulated and measured results for main parameters such as return loss, impedance bandwidth, radiation patterns and gains are also discussed herein. The study shows that modeling of such antennas, with simplicity in designing and feeding, can well meet millimeter-wave wireless communication.

Ultrawideband (UWB) Antennas With Multiresonant Split-Ring Loops

Novel ultrawideband (UWB) antennas with multiresonant split-ring loops and with coplanar waveguide (CPW) feed are presented in this communication. Dual concentric microstrip split-ring loops with different geometrical ground planes have been analyzed and compared. UWB antennas are designed, of which the dimension of each split-ring loop varies proportionally to the arithmetic progression sequence. The dimensions of the rectangular ground planes and the split-ring loops are tuned for achieving a very wide bandwidth. A tapered transmission line is adopted to improve the return loss performance in the required band. Measurement results show that the proposed UWB antennas have a wide bandwidth from 2 to 20 GHz, and the measured return losses are less than -10 dB in this band combined with relative stable radiation characteristics.

On the Performance of Printed Dipole Antenna With Novel Composite Corrugated-Reflectors for Low-Profile Ultrawideband Applications

An investigation of the performance of printed dipole antenna with finite periodically corrugated-reflectors for low-profile ultrawideband (UWB) applications is presented. According to the relative orientations of the linear-polarized source antenna and the corrugated-reflectors, the problem could be divided into H and E cases. Their fundamental differences and design guidelines are discussed in detail. A novel composite corrugated-reflector based on the combinations of H-type and E-type ones is proposed for the first time, and fully characterized with a UWB source dipole which was optimized in the free space for better comparisons. An example antenna with only 21 mm core profile, composed of a printed UWB dipole, a microstrip balun and a composite corrugated-reflector, has an impedance bandwidth of 2.75 GHz to 8.35 GHz. Both numerical and experimental results show that the example antenna also has stable uni-directional radiation patterns and a realized gain of over 6 dB within the frequency band from 2.3 to 6.0 GHz, which could be a decent alternative to the EBG antennas due to significant improvements on pattern and gain bandwidth.

A Single-Layer Ultrawideband Microstrip Antenna

A single-layer microstrip antenna for ultrawideband (UWB) applications, in which an array of rectangular microstrip patches was arranged in the log-periodic way and proximity-coupled to the microstrip feeding line, is presented. In order to reduce the number of microstrip patches in the UWB log-periodic arrays, a large scale factor k = 1.1 was firstly reported and proved to be highly effective. Furthermore, instead of using an absorbing terminal loading, a novel loss-free compensating stub was proposed. Detailed parameters study was also presented for better understanding of the proposed antennas. The impedance bandwidth (measured VSWR < 2.5) of an example antenna with only 11 elements is from 2.26-6.85 GHz with a ratio of about 3.03:1. Both numerical and experimental results show that the proposed antenna has stable directional radiation patterns, very low-profile and low fabrication cost, which are suitable for various broadband applications.

Design of a CPW-fed Ultra Wideband Crown Circular Fractal Antenna

A new ultra wideband antenna fed by coplanar waveguide (CPW) is presented in this paper. A fractal structure is constructed to obtain ultra wideband (UWB) performance. The parameters and characteristics of the antenna and the simulation results show that the 6:1 or more bandwidth is achieved with the second order iterative antenna structure

A Broadband Dual Circularly Polarized Patch Antenna With Wide Beamwidth

A broadband dual circularly polarized patch antenna with wide beamwidth is presented. The patch is excited by four cross slots via a microstrip line with multiple matching segments underneath the ground plane. The four cross slots and the multiple matching segments are optimized simultaneously to obtain the best performance. Measurements show that the antenna has 10-dB return-loss bandwidth of 24%, 10-dB isolation bandwidth of 19%, 3-dB axial-ratio bandwidth of 16%, and beamwidth of 110 °. Moreover, the single feed makes it a good candidate for array design.

Numerical Study of the Near-Field and Far-Field Properties of Active Open Cylindrical Coated Nanoparticle Antennas

A very electrically small, active open cylindrical coated nanoparticle model is constructed, and its electromagnetic properties are investigated in the visible frequency band. Its optical response under both planewave and electric dipole antenna excitations shows very strong dipole behavior at its lowest resonance frequency. The scattering cross section at that dipole resonance frequency is increased by more than +50 dBsm for the planewave excitation. When the open structure is excited by a small current (I0 = 1 ×10-3A) driven dipole antenna, the maximum radiated power of the composite nanoantenna can be increased by +83.35 dB over its value obtained when the dipole antenna radiates alone in free space. The behaviors under various locations and orientations of the dipole are explored. Dipole orientations along the cylinder axis and symmetric locations of the dipole produced the largest radiated power enhancements.

Fast parameter extraction for multiconductor interconnects in multilayered dielectric media using mixture method of equivalent source and measured equation of invariance

Measured equation of invariance (MEI) has been successfully used in many applications. It has been illustrated that the MEI is specially suitable for the decrease of computation time and computer memory space. However, for multiconductor interconnects in multilayered dielectric media, the Greens function is complex and the integrals of Sommerfeld type are time consuming. In this paper, equivalent source and measured equation of invariance (ES-MEI), a modification of the MEI, has been presented. Based on the equivalent principle, a reasonable illustration of the MEI can be obtained by ES-MEI. The node number is further decreased and the integrals of metron multiplied Greens function are avoided. It will be verified by several examples that the ES-MEI is very suitable for fast parameter extraction for multiconductor interconnects in multilayered dielectric media.