Bandstop Filter Decoupling Technique for Miniaturized Reconfigurable MIMO Antenna
Bandstop Filter Decoupling Technique for Miniaturized Reconfigurable MIMO Antenna
Blog Article
IMMEDIATE RELEF In this work, a switchable bandstop filter is used as a decoupling structure for developing a miniaturized reconfigurable multiple input multiple output (MIMO) antenna.Initially, a dual band ((2.43-2.
60 GHz and 3.51-3.79 GHz)) single monopole antenna structure is developed on FR4 substrate.
Then the single monopole antenna and its replica are accommodated in a small space with an edge to edge separation distance of 11 mm to form a 2 port MIMO antenna.Now, a switchable bandstop filter is used as a decoupling network between two closely spaced monopole antenna elements to prevent mutual coupling and reconfigure the antenna characteristics.The dual pole switchable bandstop filter is configured in such a way that one of its poles lies at 2.
5 GHz in one state (Mode 1) and at 3.68 GHz in another state (Mode 2) under the switching action of two PIN diodes.Controlling the ON/OFF states of the PIN diodes in the bandstop filter, high isolation is achieved alternately in lower (2.
43-2.60 GHz) and upper (3.51-3.
79 GHz) frequency bands of the MIMO antenna.Also, stub network is used to improve impedance matching in the upper frequency band.The proposed isolation technique helps the antenna to yield high isolation (>30 dB), fair gain (>2.
97 dBi), reasonable radiation efficiency (>86.8 %), low envelope correlation coefficient (< 0.16), high diversity gain (DG >9.
88 dB), low Mean effective gain ratio (MEG 1/MEG 2 < 0.05 dB) and block set low channel capacity loss (CCL < 0.06 bits/s/Hz) for both the operating frequency bands.
The overall dimension of the antenna is restricted to 44mm $ imes $ 22mm ( $0.36lambda _{o},, imes ,,0.18lambda _{o}$ ) for its easy integration in compact wireless devices.
This type of reconfigurable MIMO antenna is best suited for cognitive radio communication, which promotes efficient spectrum utilization.