Shanpu Shen

Designing dual-port pixel antenna for ambient RF energy harvesting using genetic algorithm

In this paper we provide a design for a dual-port pixel antenna for energy harvesting in ambient RF electromagnetic fields. We use Z-parameters to analyze the equivalent circuit network of the antenna and find the relationship between the connections of the pixels in the antenna and the received power. Finding the optimal connection configuration for the pixels which maximizes the power over a frequency band is then achieved by using the genetic algorithm. The simulation result shows that the proposed dual-port antenna can achieve a better power performance than a single dipole antenna of similar size. Measurement results are also provided.

Impedance Matching for Compact Multiple Antenna Systems in Random RF Fields

We investigate the maximization of the received power from compact multiple antenna systems in random RF fields, using two novel impedance matching approaches. The first approach is based on optimal impedance matching where we use convex optimization to propose a sparse optimal impedance matching technique. The second approach is obtained by further relaxing the sparse optimal impedance matching method to obtain a suboptimal impedance matching (SOM) method we refer to as multiport ladder matching (MLM). Simulation results show that the sparse optimal impedance matching approach provides the maximum received power while MLM can capture more power than conventional single-port matching (SPM). Additionally, they can maintain good bandwidth indicating the effectiveness of the sparse optimal and multiport ladder impedance matching approaches.

A broadband l-probe microstrip patch rectenna for ambient RF energy harvesting

In this paper we present a design for a broadband L-probe microstrip patch rectenna for ambient RF energy harvesting. The broadband L-probe microstrip patch antenna can receive ambient RF signals from UMTS-2100 band (2110–2170 MHz) and WLAN band (2400–2500 MHz) to harvest energy. We provide simulation and measurement results of the broadband L-probe microstrip patch antenna. We also provide results for a dual-band rectifier working in the UMTS-2100 band and WLAN band which is also optimized.

Successive Boolean Optimization of Planar Pixel Antennas

We propose a novel heuristic method for optimizing planar pixel antennas which we refer to as successive exhaustive Boolean optimization (SEBO). The key step in SEBO is to cyclically optimize a multivariable binary optimization problem by exhaustively searching a subset of binary variables. An adaptive version of SEBO is also introduced. We provide both simulation and experimental results for optimized antennas covering single and dual bands for mobile phone applications. Comparisons with genetic algorithms, binary particle swarm optimization, and angle modulate differential evolution are also provided and these show that SEBO and adaptive SEBO have up to 50% less computational complexity and can satisfy the design objective more consistently. A major advantage of SEBO and adaptive SEBO is that only one parameter needs to be set up for the optimization, while for evolutionary optimization two or more parameters usually need to be set up.

Multi-port ladder impedance matching for compact MIMO communication systems

We investigate multi-port ladder impedance matching (MLM) for enhancing the capacity of compact MIMO communication systems. MLM builds upon single-port matching (SPM) techniques by incorporating an additional reactance that connects adjacent antenna ports together and promises enhanced performance while maintaining good bandwidth. We demonstrate numerically for a 5-element compact MIMO system that optimum MLM can increase capacity by up to 9% compared to SPM. In addition we also show that over wide bandwidths MLM performs better than SPM.

Dual-band antenna pair for MIMO WiFi compact mobile terminals

In this paper a compact dual-band WiFi antenna pair is proposed which is suitable for compact mobile terminals such as smart phones. The proposed antenna pair is wrapped on a 20.8×3.3×2.7 mm3 spacer and is located at the edge of a 122×62 mm2 ground plane. The antenna geometry advantage is that it allows mobile phone manufacturers to accommodate four antenna elements for Multiple-Input Multiple-Output (MIMO) WiFi applications in their products. Apart from antenna characterization, channel capacity of the proposed antennas is also provided.

Optimization of 2.45-GHz pixel rectenna for wireless power transmission using mixed integer linear programming

In this paper we provide a 2.45-GHz pixel rectenna design for wireless power transmission. We propose a deterministic optimization method called Mixed Integer Linear Programming (MILP) to optimize the pixel antenna. The global optimal hardwire of the pixel antenna is simulated, fabricated, and measured. An optimized 2.45-GHz rectifier is also proposed and simulated in this paper

Transparent dual-band antenna for smart watch applications

In this paper an optically transparent dual-band antenna is proposed. The antenna can be directly constructed on the surface of display screens for applications in smart watches, tablets and smart TVs. This design approach would relieve the antenna designer of having to integrate antennas into the body of electronic devices and allow them to integrate antennas into the display and provide significant advantages in small form factor and low profile wireless communication apparatus. It is shown that the proposed antenna can exhibit dual-band operation.