Liping Han

Design of Compact Differential Dual-Frequency Antenna With Stacked Patches

A compact differential dual-frequency antenna with stacked configuration is described. Compared with the conventional stacked dual frequency antenna, the radiating element with a half guided wavelength is distributed on two layers and connected through via holes, thus the dimension of the antenna is reduced effectively. In order to improve the bandwidth at the first resonant frequency (f1), a reflecting board is introduced and connected with the ground plane through three via holes. As a result, a new resonant frequency closing to f1 can be excited and the bandwidth at fx is enhanced. Both differential antennas with and without the reflecting board are fabricated and measured. The realized antennas have a compact size of 15 mm × 15 mm, which equals to 0.23¿1 × 0.23¿1 (¿1, the guided wavelength at f1). Experimental results show that the proposed antenna can operate at 2.4 GHz and 5.2 GHz bands. Good agreement between the simulated and measured results is obtained.

A Compact Ultrawideband Diversity Antenna With High Isolation

A compact ultrawideband (UWB) polarization diversity antenna with high isolation is designed in this letter. It comprises a step-tapered slot antenna (S-TSA) and a small square monopole antenna with an inverted H-shaped slot and an H-shaped conductor-backed plane. The isolation between the two ports is improved due to the orthogonality of E-field of two elements. The designed antenna has a small size of 26 × 38 mm2. The measured results show that it can operate from 3.1 to 10.6 GHz, in which the average isolation is better than 30 dB.

Angle-Based Chipless RFID Tag With High Capacity and Insensitivity to Polarization

This paper presents a novel angle-based chipless radio frequency identification (RFID) tag with high capacity that is polarization-independent. Its scatterer is designed to be V-shaped. It encodes data using the space angle between two arms of the V-shape and is identified by measuring the scattered field in two orthogonal polarization directions. Even if it is tilted, the tag can be identified. The advantage of angle-based tag is that every element can encode three-bit data. This is helpful to get higher capacity. Also, for different codes of one element, the proposed tag uses the same spectrum. This is beneficial to improve the efficiency of the spectrum. First, the tag using the uniform impedance resonator (UIR) is designed. Then, the UIR chipless tag is reformed as stepped impedance resonator (SIR) tag to suppress the second harmonic. The realized tags operate in the frequency range 1.83-2.15 GHz and the identification errors are less than 3.9°. Every element of the realized tags can carry 3 bits of coding information.

Compact Frequency-Reconfigurable Slot Antenna for Wireless Applications

A compact frequency-reconfigurable slot antenna for LTE (2.3 GHz), AMT-fixed service (4.5 GHz), and WLAN (5.8 GHz) applications is proposed in this letter. A U-shaped slot with short ends and an L-shaped slot with open ends are etched in the ground plane to realize dual-band operation. By inserting two p-i-n diodes inside the slots, easy reconfigurability of three frequency bands over a frequency ratio of 2.62:1 can be achieved. In order to reduce the cross polarization of the antenna, another L-shaped slot is introduced symmetrically. Compared to the conventional reconfigurable slot antenna, the size of the antenna is reduced by 32.5%. Simulated and measured results show that the antenna can switch between two single-band modes (2.3 and 5.8 GHz) and two dual-band modes (2.3/4.5 and 4.5/5.8 GHz). Also, stable radiation patterns are obtained.

Differential Dual-Band Antenna-in-Package With T-Shaped Slots

A differential dual-band antenna-in-package (AiP) with multilayer structure is proposed. Compared to the normal antenna, the introduced package structure changes the impedance of the antenna, such that the new resonant frequency is excited. Then, a dual-band antenna is realized. Also, in order to improve the radiation pattern in higher band, two symmetrical T-shaped slots are etched on the patch. The T-slots can help to widen the bandwidths. The realized AiP can work at 2.49 and 5.8 GHz. The 10-dB relative bandwidth is 1.61% (2.47 ~ 2.51 GHz) and 5.51% (5.67 ~ 5.99 GHz), respectively.

Modeling and Design of Microstrip Patch Antenna-in-Package for Integrating the RFIC in the Inner Cavity

This letter presents the circuit model of the antenna-in-package (AiP) for integrating the RFIC in the inner cavity. The closed-form expression for the inductance of the ground via is provided in the case that two ground vias are arranged under the nonradiating edge of the AiP. The new expression takes account of the radius and length of the vias, the relative positions of vias, and the distances between via holes and the feeding point of the antenna. Based on the circuit model, the influences of vias on the performance of the AiP are analyzed. It is found that the bandwidth of the AiP can be effectively improved by properly arranging two via holes under the nonradiating edge of the antenna. Finally, an AiP with the center frequency of 5.12 GHz is realized, and a bandwidth of 400 MHz is obtained. The calculated results are in agreement with the simulated and measured.

A Novel Differential Dual-Band Bandpass Filter Based on Stepped-Impedance Double-Sided Parallel-Strip Line

Abstract A novel differential dual-band bandpass filter based on a stepped-impedance double-sided parallel-strip line is proposed in this article. In order to suppress the common-mode signal, an H-shaped ground plane is inserted. The simulated and measured results show that the proposed filter operated at 2.4 GHz and 5.8 GHz with the insertion losses of 3.2 dB and 3.5 dB, respectively. Also, the common-mode signal is suppressed to below −30 dB from 1 GHz to 7.5 GHz.

Design of CPW-fed tri-band coplanar slot antenna

In this paper, a tri-band coplanar slot antenna fed by a coplanar waveguide is designed and it contains multiple slot segments with different lengths and widths between the patch and the ground conductors. By analyzing the effect of each slot segment, it is found that the tri-band antenna can be realized by adjusting the size of each slot segment properly. The proposed structure is used to design a 2.4/3.8/5.8 GHz tri-band antenna with the size of 29 mm×40 mm. The simulated results indicate the designed antenna operates in the required three bands, which have the bandwidths (reflection coefficient< −10dB) of 260 MHz, 240 MHz and 150 MHz, the peak gains of 2 dBi, 3.1 dBi and 2.7 dBi, respectively.

Design and Performance Study of a Differential Dual-Band Antenna-in-Package

ABSTRACT This article presents a differential dual-band antenna-in-package (AiP) for wireless local area network applications. Dual-band operation is realized by a square ring and a pair of fork-shaped strips. For AiP, there will be an interaction between the antenna and packaged component, which usually takes place in the near field. By using two non-uniform via fences, the bandwidth at two bands is significantly improved, and the electric field in the package cavity is also effectively suppressed. The distribution of the electric field in the package cavity is analyzed, and then a method that arranges the via fences connecting the antenna ground and package ground is demonstrated. Simulation and experiment results show that the proposed AiP can operate at 2.4 and 5.2 GHz, and the relative impedance bandwidth is broadened to be 8.7 and 15.2%, respectively. Moreover, good radiation performances are achieved at two bands.

Compact dual-band dipole antenna fed by a coplanar waveguide

A compact dual-band dipole antenna fed by a coplanar waveguide for wireless communication is presented in this paper. The dual-band antenna consists of a long dipole and a short dipole, which were designed for operation at the lower and upper bands, respectively. The miniaturization is achieved by meandering slits in the long dipole. The simulated results show that the antenna can operate at 2.44 GHz and 5.18 GHz. In addition, omnidirectional radiation patterns are achieved at two operating bands.