Isolation enhancement between two closely packed antennas

A. C.K. Mak, C. R. Rowell, R. D. Murch

Research output: Contribution to journalArticlepeer-review

300 Citations (Scopus)


This paper introduces a coupling element to enhance the isolation between two closely packed antennas operating at the same frequency band. The proposed structure consists of two antenna elements and a coupling element which is located in between the two antenna elements. The idea is to use field cancellation to enhance isolation by putting a coupling element which artificially creates an additional coupling path between the antenna elements. To validate the idea, a design for a USB dongle MIMO antenna for the 2.4 GHz WLAN Band is presented. In this design, the antenna elements are etched on a compact low- cost FR4 PCB board with dimensions of 20 × 40 × 1.6 mm3. According to our measurement results, we can achieve more than 30 dB isolation between the antenna elements even though the two parallel individual planar inverted F antenna (PIFA) in the design share a solid ground plane with inter-antenna spacing (Center to Center) of less than 0.095 λo or edge to edge separations of just 3.6 mm (0.0294 λo). Both simulation and measurement results are used to confirm the antenna isolation and performance. The method can also be applied to different types of antennas such as non-planar antennas. Parametric studies and current distribution for the design are also included to show how to tune the structure and control the isolation.

Original languageEnglish
Pages (from-to)3411-3419
Number of pages9
JournalIEEE Transactions on Antennas and Propagation
Issue number11
Publication statusPublished - Dec 10 2008


  • Diversity antennas
  • Multiple input and multiple output (MIMO)
  • Mutual coupling
  • Planar inverted F antenna (PIFA)
  • Wireless communications

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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