Study on Mutual Coupling Reduction Technique for MIMO Antennas

Abstract

In recent years, multiple-input-multiple-output (MIMO) antennas with the ability to radiate waves in more than one pattern and polarization play a great role in modern telecommunication systems. This paper provides a theoretical review of different mutual coupling reduction techniques in MIMO antenna systems. The increase in the mutual coupling can affect the antenna characteristics drastically and therefore degrades the performance of the MIMO systems. It is possible to improve the performance partially by calibrating the mutual coupling in the digital domain. However, the simple and effective approach is to use the techniques, such as defected ground structure, parasitic or slot element, complementary split ring resonator, and decoupling networks which can overcome the mutual coupling effects by means of physical implementation. An extensive discussion on the basis of different mutual coupling reduction techniques, their examples, and comparative study is still rare in the literature. Therefore, in this paper, different MIMO antenna design techniques and all of their mutual coupling reduction techniques through various structures and mechanisms are presented with multiple examples and characteristics comparison.

Dual band frequency tunable planar inverted‐F antenna for mobile handheld devices

“…The fixed capacitor or dc block capacitor is implemented in the main PIFA radiating element to avoid dc shorting. It also helps in impedance matching by canceling the small input inductance of the antenna and typically used to isolate the parts of the antenna that need to be biased . It is placed between the lower band region and higher band region to achieve independent frequency tunability.…”

“…It also helps in impedance matching by canceling the small input inductance of the antenna and typically used to isolate the parts of the antenna that need to be biased. 18 It is placed between the lower band region and higher band region to achieve independent frequency tunability. A 10 kΩ resistor is also used in LB and HB section to bias the varactor diodes at the point P 1 and P 2 .…”

Beam scanning annular slot‐ring antenna array with via‐fence for wireless power transfer

“…The coupling between elements varies the antenna characteristics and prohibits compactness. Various research works have been conducted to study the mutual coupling effect in an array and various techniques have been proposed to reduce the mutual coupling . Parasitic patches and parasitic meander line, soft or hard surfaces, defected ground structure, bandgap structure, metamaterial, and electromagnetic three‐dimensional (3D) wall are a few techniques proposed in the literature to reduce mutual coupling by blocking or minimizing surface current flow.…”

Bandwidth Enhancement and Mutual Coupling Reduction Using a Notch and a Parasitic Structure in a UWB-MIMO Antenna

“…Even though MIMO technology is better than singleinput, multiple-output (SIMO) or multiple-input, singleoutput (MISO) in terms of channel capacity, it has some limitations regarding the correlation between the antennas and realizing space efficiency [2]. Improving the isolation factor or correlation in a MIMO antenna using various types of coupling and decoupling structures is achieved at the expense of size and space [3].…”