Qinjiang Rao

HANDSET ANTENNA DESIGN: PRACTICE AND THEORY

In this paper, an attempt is made to present a theory for the design of handset antennas, which results from the long experience that the authors have in the field of handset antenna design. The proposed theory is based on the well-known skin effect and constructs the antenna using a thin wire model that represent the backbone of the final antenna. The analytical solution for the thin wire model is first obtained, and the main properties (such as the return loss and the radiation properties) of the antenna can then be studied using this analytical solution. Once the antenna backbone is constructed, other elements, such as stubs, patches, etc., can be added to optimize the match at the desired frequency bands. A number of numerical and analytical examples are provided throughout the paper to validate the theory. Different antenna types, such as wire antennas and planar antennas, are tested and designed using the thin wire model. The correspondence between the analytical results and those from the numerical simulations using full-wave solvers agree very well in all examples. The authors also present in this paper a novel design of three small antennas for handset applications, which are based on the simple wire monopole, but in a three-dimensional form. The proposed three-dimensional monopole antennas have multi-band and broadband properties that cover most frequency bands being used for the handset device. The antennas feature remarkable properties while occupying a significantly small space, which makes them strong candidates for handset applications and for the future multi-antenna applications too.

A Compact, High Isolation and Wide Bandwidth Antenna Array for Long Term Evolution Wireless Devices

A compact dual-port, multiple input-multiple output (MIMO) antenna array for handheld devices is introduced. The antenna structure consists of two quarter wavelength monopole slots etched on the ground plane of a printed circuit board (PCB) and a meandered slot cut between them. The meandered slot not only reduces the coupling between the two slot antennas, but also improves the bandwidth and efficiency of the array by acting as a radiating parasitic element. Simulated and measured results show that the meandered isolating slot allows the antennas to achieve wider bandwidth, higher efficiency, higher isolation and better diversity performance, compared to other types of isolating slots.

Compact Multiband Antenna for Handheld Devices

A compact multiband antenna is presented for wireless handheld devices. The proposed design uses two folded L-shaped strips connected by a short stub and fed from a common excitation. Compared to other available multiband antenna designs, the proposed design has simpler structure, smaller size, and higher mode independence.

Compact low coupling dual -antennas for MIMO applications in handheld devices

A dual-port slot strip antenna array for MIMO handheld devices is presented. This antenna array uses a T-shaped slot with changed widths to improve isolation between the two ports. The antenna has the combination of omni-directional radiation, high efficiency and compact size in an easy to fabricate structure. The experimental and simulated results validate the proposed design.

Ultra -small cubic folded strip antenna for handset devices

A ultra-small 3 dimensional folded strip antenna is proposed for handset devices. The volume of the antenna is very small compared to traditional PIFA design. The wrapping or bending of the wire (or strip) controls the radiation patterns and enhances the antenna bandwidth. The performance of the three dimensional strip antennas is much better than that of a PIFA with the same maximum size. Because of the small size, the proposed three dimensional monopole antennas may be deployed in a handset as antenna elements to form a multiple antenna system, such as a smart antenna array or a multi-input and multi-output (MIMO) system.

Compact mufti-feed mufti-band antenna designs for wireless mobile devices

In this paper, we present a multi-feed multi-band planar antenna. Through the simulation and measurement of several prototypes, we demonstrate that the proposed design allows a single antenna to cover multi-bands without increasing antenna volume. The proposed design is especially suitable for nowadays wireless mobile devices.

Numerical calculations of the information capacity of a transmitting antenna

We discuss the information capacity of the transmitting antenna through numerical examples. Antennas with different radiation proportions are considered. It is shown that given an antenna geometry and characteristics, the antenna information capacity can be measured and is limited by an upper bound. We also show that the capacity of a directional antenna is greater than that of an omnidirectional antenna for a given size.

Electromagnetically coupling fed broadband low profile microstrip antenna array

This paper presents an electromagnetically coupling fed broadband low profile microstrip antenna (MSA) array. Radiation element is an E-shaped MSA that is fed by an electromagnetically coupled strip and covered by a low loss radome. Each radiation element is connected to a 8 by 8 parallel feed network where a 50 ohm coaxial feed is located at the center of the array. The impedance bandwidth for the return loss of 10 dB covers 4.5 to more than 6.5 GHz with the peak gain from 18 to 21 dBi. The height from the ground plane to the top of the radome is about 8 mm. The developed antenna structure is suitable for base station antennas in wireless communication systems.

Link-layer performance of 2×2 780MHz and 2×2 2.3GHz MIMO systems

Link layer capacities of 2.3GHz and 780MHz antennas in 2×2 MIMO systems are compared. Simulation results show comparable performance for these two systems. Although a much better performance was expected from the 2.3 GHz system compared to the 780MHz system, the orientation of the antenna pattern played a significant factor in link layer performance. In the simulated designs, the orientation of the antenna pattern favored the 780MHz antennas.

A multi-band antenna for potential 700 MHz handheld device applications

This paper presents a single feed small size multi-frequency band antenna. The antenna is composed of several folded conducting strips and an L-shaped ground plane. Simulated and measured results show that in addition to a lower frequency band for 700 MHz band wireless applications, the antenna can operate at higher frequency bands of GSM/800/900/1800/1900 and UMTS 2100 and the antenna feature high radiation efficiency with compact size.