Guorui Han

An Integrated Approach to RF Antenna-Filter Co-Design

In this letter, a co-designed antenna-filter is presented. The antenna-filter is composed of a microstrip patch antenna and a hairpin filter, both of which share the same ground plane to reduce the size. Instead of using the traditional 50-Omega interfaces, the impedance between the filter and antenna is optimized to improve the performance. The simulated and measured results have demonstrated that co-designed antenna-filter has a better bandwidth (4.7%, 4.064.26 GHz) and a larger gain (4.3 dBi) than the traditional version with 50-Omega interfaces impedance.

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.

Calibrating an Arbitrary Test Fixture for a Symmetric Device by Three Measurements

In this paper, a general solution of calibrating a microwave test fixture for a symmetric device is deduced from the cascading network relation, and it exposes the probability and condition of calibrating an arbitrary test fixture for a symmetric device by three measurements, which is less than the times of measurements in the thru-reflect-line (TRL) method. The scattering parameters of the test fixture and the embedded symmetric device can be determined by measurements of a thru, a line, and the symmetric device. Furthermore, the method is analyzed and verified by simulation and measurement. The analysis indicates that the presented method is suitable for determining the calibrated S-parameters of a symmetric device under test (DUT).

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.

Electromagnetic Mode Theory of Periodically-Loaded Oversized Imperfect Waveguide and Its Application to the Propagation of Radio Waves in Long Wall Coal Mining Face Tunnels

A long wall coal mining face tunnel is idealized as a periodically-loaded oversized imperfect rectangular waveguide. A rigorous solution for the electromagnetic field distribution is presented. The theoretical analysis is mainly concentrated on obtaining the characteristic equations for HEM and TE modes and reductions are carried out to obtain the mode equations in a form suitable for the numerical computation. The propagation constant of the TEm0 mode is computed. The calculated and measured propagation attenuation rates of the dominant TE10 mode are compared for a scaled model. They are in good agreement, showing the validity of the theory.

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.

Co-design method for dual-band low-noise amplifier and band-pass filter

A co-design method for the dual-band low-noise amplifier (LNA) and band-pass filter (BPF) is presented in this study. The dual-band BPF and LNA are designed separately by the traditional method first. In order to reduce the circuit, the dual-band matching networks (MNs) of the LNA and BPF are combined into the dual-band matching-filter. The validity is verified by a sample of 1.57/2.4 GHz LNA-filter after the co-design. The measured S21, NF and BW3 dB are 18.6 dB, 1.98 dB and 0.22 GHz at 1.57 GHz, and 15.2 dB, 1.95 dB and 0.3 GHz at 2.31 GHz, respectively. The results indicate that the co-design and cascade versions have same performance, but the co-design version cuts down the number of the passive components by nearly half.

A wideband dual-polarized patch antenna fed with the aperture-coupled microstrip

ABSTRACT In this paper, a compact broadband dual-polarized stacked patch antenna with the aperture coupled microstrip feed is proposed. By adding a parasitic disc patch, the bandwidth is effectively broadened. Meanwhile, to improve the isolation at the low frequency band, a rectangular slot is etched along the diagonal line of the ground plane. The measured results show that the proposed antenna can operate from 9.6 to 22.4 GHz and the relative bandwidth is 80%. Also, the isolation within the operating frequency band is better than 15 dB and the maximum gain reaches 4.08 dBi.

A novel MIMO antenna with DGS for high isolation

A novel four port multiple-input-multiple-output (MIMO) antenna at 2.4 GHz ISM band is designed in this paper. The MIMO antenna includes an octangular patch surrounded by a square ring patch. The overall system dimension is 60 × 60 × 1.6 mm3. The antenna operates in a 50 MHz bandwidth centered at 2.44 GHz. A defected ground structure (DGS) for improving the isolation between four ports is proposed. Isolation improvement by 10 dB is achieved and mutual coupling values as low as -23.6 dB are obtained between antenna elements.

Study on a Novel Broadband Planar Dual-Polarized Antenna

ABSTRACT In this article, a novel broadband dual-polarized antenna is proposed. It is fed by the microstrip and co-planar waveguide to realize the horizontal and vertical polarization. Its radiating element is a rectangular monopole. To broaden the bandwidth, the rectangular monopole is changed into a gradient one. Meanwhile, two symmetrical rectangular slots are etched in the ground plane. The measured results show that the bandwidths of the two ports are from 2.2 to 3.9 GHz and from 1.9 to 4.4 GHz, respectively. The corresponding impedance bandwidths are 79.4% and 55.7%, respectively. The isolation between the two input ports is better than 20 dB. The simulated result agrees well with the measured one.