Compact and closely spaced tunable printed F‐slot multiple‐input–multiple‐output antenna system for portable wireless applications with efficient diversity

Abstract

In this work, miniaturized tunable two-antenna MIMO systems composed of printed F-slot shaped is developed to operate in the GPS, PCS, DCS and UMTS bands. The two-element MIMO antenna occupies a volume of 50 × 37.5 ×1.6 mm 3 , and is printed on an FR4 substrate. Initially, the frequency tunability of the MIMO antennas was verified by lumped capacitors with values between 0.75 to 2.75 pF to achieve a tuning range from 1.55 to 2.07GHz while the low mutual coupling between the radiators was accomplished by adding an I-shaped branch to a cut-away ground plane. The two antennas are then loaded with varactors to simultaneously achieve miniaturization and tunability. Simulation and measurement results demonstrate the successful implementation of a tunable MIMO with coupling reduction mechanism for a portable handheld wireless transceiver. The channel capacity of the proposed antenna is investigated and found to be close to that of an uncorrelated system with efficient diversity in which the mutual coupling across the full bandwidth was better than -13dB. Owing to the compact size and ease of manufacture, the proposed antennas can be a promising solution for adaptive MIMO systems in handheld devices.

Dual-Band MIMO Balanced Antenna for C-Band and WLAN Applications

“…It is noticeable, that the ECC of the proposed two-element antenna is kept below 0.01 at the dual desired bands of 4GHz and 5GHz. This is comparable to the results obtained from [1][2], which suggests good diversity performance. The other paramount factor is the channel capacity.…”

“…= (1) In order to investigate the performance of the MIMO antenna, the calculated ECC is illustrated in Figure 7,a. It is noticeable, that the ECC of the proposed two-element antenna is kept below 0.01 at the dual desired bands of 4GHz and 5GHz.…”

“…In this case, the correlation coefficients between MIMO antenna elements are very high in which leads to a severe drop in the antenna efficiency. Lately, a large number of MIMO antennas along with numerous techniques for reducing mutual coupling between the MIMO antenna elements in compact mobile handsets have been proposed [1][2][3][4][5][6][7][8]. However, all these MIMO antennas are made with unbalanced structure, which are ground plane independent, and as a result, are sensitive to user hand held effects [9].…”

Mutual Coupling Reduction of Two 2x1 Triangular-Patch Antenna Array Using a Single Neutralization Line for MIMO Applications

“…The trend in the industry is getting smaller and more integrated devices, making difficult to keep their MIMO antennas away to each other. Many techniques intended to reduce the electromagnetic coupling between MIMO ports can be found in literature, for instance neutralization lines [3][4][5], EBG and metamaterial structures [6][7][8], modifications on the ground plane between the antennas [9], [10], coupling/decoupling networks [11], [12], parasitic scatterers [13], [14], and so on. It is noticeable that the efforts had been focused in one-element antennas, and far from abundant work had been done about improving the decoupling between antennas consisting of array of radiators.…”