Changjiang Deng

A Wideband Sequential-Phase Fed Circularly Polarized Patch Array

This communication presents a wideband circularly polarized (CP) 2 × 2 patch array using a sequential-phase feeding network. By combining three operating modes, both axial ratio (AR) and impedance bandwidths are enhanced and wider than those of previous published sequential-fed single-layer patch arrays. These three CP operating modes are tuned and matched by optimizing the truncated corners of patch elements and the sequential-phase feeding network. A prototype of the proposed patch array is built to validate the design experimentally. The measured -10-dB impedance bandwidth is 1.03 GHz (5.20-6.23 GHz), and the measured 3-dB AR bandwidth is 0.7 GHz (5.25-5.95 GHz), or 12.7% corresponding to the center frequency of 5.5 GHz. The measured peak gain is about 12 dBic and the gain variation is less than 3 dB within the AR bandwidth.

Dual-Band Circularly Polarized Rotated Patch Antenna With a Parasitic Circular Patch Loading

A dual-band circularly polarized (CP) rotated patch antenna is proposed in this letter. Dual-band CP operation of the proposed antenna is achieved by adopting a circular patch below the rotated rectangular patch. The extra circular patch not only provides a higher band, but is also employed to tune the operating frequency of the lower band, which is generated by the rotated rectangular patch. The rectangular patch and the circular patch can be arranged on the front and back of a thin substrate and fed by a single slot. The dual CP operating bands can be tuned separately with a small frequency ratio of 1.18. A prototype of the proposed antenna is built to validate the design strategy. The measured 3-dB axial-ratio (AR) bandwidth is 2.1% (2.238-2.285 GHz) for the lower band and 2.0% (2.645-2.695 GHz) for the higher band, with the reflection coefficient being lower than -10 dB. The radiation pattern and gain are also measured and compared to the simulated ones.

A Wideband High-Isolated Dual-Polarized Patch Antenna Using Two Different Balun Feedings

In this letter, a dual-polarized patch antenna with low profile and wide bandwidth is presented. The square patch, where a bow-tie slot is etched on, is excited by two different balance-to-unbalance feedings for dual polarization. One of the polarizations is excited by the central-placed transition, which transfers the unbalanced microstripline feed to the balanced slot feed. The other polarization is excited by a differential feed network, which contains two capacitively coupled probe feeds. By adopting the two balanced feedings, high isolation and low cross polarization are achieved. A prototype of the proposed antenna is built and tested. Measured results show that the -10-dB reflection coefficient bandwidth of the two polarizations is about 18.8%, with port isolation less than -28.5 dB.

Planar Printed Multi-Resonant Antenna for Octa-Band WWAN/LTE Mobile Handset

In this letter, a planar printed multiple-band antenna is proposed for mobile handset applications. The antenna consists of a driven monopole with multiple branches, and a parasitic ground strip with an open slot. By properly tuning the dimensions and positions of each part of the proposed antenna, octa-band operation is achieved with good radiation efficiency. For lower frequency, the LTE700, GSM850, and GSM900 bands are provided by the λ/4 modes of the driven monopole and the parasitic ground strip. For upper frequency, the DCS, PCS, UMTS, LTE2300 and LTE2500 bands are covered by the higher order modes of the driven monopole and the parasitic ground strip. The open slot and the shorter driven branch are utilized to widen the bandwidth in the upper frequency. All the mentioned operating bands are achieved in a small area of 15 ×60 mm2. The measured -6-dB reflection coefficient bandwidth is 405 MHz ( 660 ~ 1065 MHz) in the lower band and ranges from 1665 MHz to more than 3000 MHz in the upper band.

A Wideband Isotropic Radiated Planar Antenna Using Sequential Rotated L-Shaped Monopoles

In this communication, we have proposed a compact planar antenna for isotropic radiation pattern in a wide operating band. The proposed antenna consists of four sequential rotated L-shaped monopoles that are fed by a compact uniform sequential-phase (SP) feeding network with equal amplitude and incremental 90 ° phase delay. Based on the rotated field method, a full spatial coverage with gain deviation less than 6 dB is achieved in a wide operating band from 2.3 to 2.61 GHz, also with well-impedance matching. A prototype of the proposed antenna has been built and tested. The measured results, including the reflection coefficient, gain, and radiation patterns, are analyzed and compared with the simulated results.

A Hemispherical 3-D Null Steering Antenna for Circular Polarization

In this letter, a compact three-dimensional (3-D) null steering antenna is presented for circular polarization. Two high-isolated circularly polarized (CP) pattern modes, the broadside and the conical CP pattern modes, are synthesized for 3-D null steering in the upper hemisphere. The broadside CP pattern mode is generated by a corner-truncated patch, and the conical CP pattern mode is generated by four rotationally symmetric strips. By controlling the exciting power ratio and the relative phase delay of the two modes, continuous null steering is achieved in the elevation plane and the azimuth plane, respectively. A prototype of the proposed antenna operating at 1.575 GHz is fabricated and tested for the global position system (GPS) applications. The simulated and measured results verify the null steering performance of the proposed design.

A Novel Low-Profile Hepta-Band Handset Antenna Using Modes Controlling Method

It is a challenging and tough task to achieve and tune multiple frequencies for handset antennas in a small area. In this communication, we have proposed a novel modes controlling method to build and tune the handset antenna. By combining different modes of an open slot and different monopole branches, a hepta-band, covering GSM850, GSM900, DCS, PCS, UMTS, LTE2300, and LTE2500, handset antenna is achieved in a small area of 8 × 60 mm 2. The most essential merit of the proposed antenna is that the related modes can be added step by step, according to the operating bands. The modes for the lower and upper bands can be easily tuned and optimized. We have also built a prototype of the proposed antenna to validate the design strategy. The tested results include reflection coefficient, radiation patterns, efficiency and gain.

MIMO Mobile Handset Antenna Merging Characteristic Modes for Increased Bandwidth

The behavior of a mobile handset chassis-mode antenna with a metal bezel is analyzed in this paper by utilizing the theory of characteristic modes (TCM). Two eigenmodes, one from the chassis (0.5λ-dipole mode) and the other one from the bezel (1λ-perimeter mode), are merged by a monopole exciter to broaden the antenna bandwidth below 1 GHz. A new eigenmode from the bezel (1.5λ-perimeter mode) is also exploited to achieve multiple-input multiple-output (MIMO) performance. The characteristics of the antenna are verified with an experimental prototype and measurements. The measured input reflection bandwidths from the two ports are 263 MHz (742-1005 MHz) and 93 MHz (863-956 MHz), respectively. The port isolation is more than 7.4 dB across the whole band of interest. Finally, the monopole exciter, which excites two eigenmodes in the lowfrequency band, is modified to provide more resonances in the upper frequency band, providing coverage in the range of 1715- 2060 MHz and 2280-2710 MHz.

A Circularly Polarized Pattern Diversity Antenna for Hemispherical Coverage

In this communication, a circularly polarized (CP) antenna is proposed for satellite communication applications. The proposed antenna consists of two parts. One part is in-phase-fed folded monopoles with omnidirectional CP radiation pattern, and the other part is sequential-fed L-shaped monopoles with broadside CP radiation pattern. By combining the two parts as a pattern diversity antenna, upper hemispherical coverage with left-handed circular polarization (LHCP) is achieved in a small volume of 0.38λ×0.38λ×0.071λ ( λ is the free-space wavelength). A prototype of the proposed antenna operating at 1.575 GHz has been built and tested. The measured overlapping bandwidth for both the two patterns with -10-dB impedance bandwidth and 3-dB axial-ratio (AR) is 6.7% (1.515-1.62 GHz), also with high port isolation. In addition, the AR and gain coverage over the upper hemisphere is discussed in detail.

2-D Planar Scalable Dual-Polarized Series-Fed Slot Antenna Array Using Single Substrate

This communication proposes a dual-polarized slot antenna array, which is able to expand two-dimensionally (2-D), using only one layer of substrate board. Two identical coplanar waveguide (CPW) series-fed slot arrays are positioned orthogonally, providing dual polarization with high port isolation. The overall array is arranged on both sides of a single substrate, achieving low cost in fabrication. To validate the design concept, a model of the proposed array is built for the 2.4-GHz wireless local area network (WLAN) application. We have measured S parameters, radiation patterns and gain, and compared them with the simulation results.