Combinatory Feeding Method for Mobile Applications

Abstract

This letter presents a method for implementing frequency reconfigurability without lumped elements. The method is based on feeding an antenna element simultaneously at different locations with differently delayed and amplified signals and dynamically manipulating the number of active feeds. To demonstrate the concept, an example design of a handset antenna that is compatible with most modern mobile phones is presented. The proposed antenna geometry is simple and practical, consisting only of a folded rectangular sheet and four feeding points. The simulated efficiency of the antenna is higher than 50% from nearly 0.7 to 7 GHz with the highest efficiency being above 90% in 2 × 2 multiple-inputmultiple-output (MIMO) operation.

Eight-Element MIMO Handset Based on Combinatory Feeding

“…Idea of combinatory feeding is presented and demonstrated with examples in [9]. By terminating some of the ports with an open circuit, large variety of antenna impedances can be created.…”

“…1. The design is based on the 2 x 2 handset proposed in [9] with the addition of six higher band data antennas. Each antenna is a folded rectangular sheet with four feed points.…”

“…In [9] the concept was extended to a method referred to as combinatory feeding. The frequency response of an antenna cluster can be altered by powering down some of the amplifiers on the multichannel transceiver, which further increases the tuning range of an antenna cluster.…”

Adjusting Radiation Pattern of Small Antennas

“…The feeds can have even a galvanic connection, i.e. they are strongly connected to the same antenna element [4]. If matching level is better, less coupling is required and the antenna cluster can also be distributed [5].…”

Finding Optimal Total Active Reflection Coefficient and Realized Gain for Multi-port Lossy Antennas

“…W ITH increasing interest in multi-port and MIMO systems, see, e.g., [1], [2], [3], [4], [5], [6], a new set of figure of merits were needed to judge their performance. Among the few available choices, the total active reflection coefficient (TARC) [7], [8], [9] became widely used, due mainly to its straightforward definition and experimental accessibility.…”