Small-Sized UWB MIMO Antenna With Band Rejection Capability

Abstract

A very compact and small sized 2-element planar Ultra Wide band (UWB) antenna having high isolation with band rejection characteristics designed on a FR4 substrate (23 × 26 × 0.8 mm 3 ) is presented in this paper. Each antenna element have a rectangular stepped-slot and a z-shaped slot, both etched in ground plane. The rectangular slot, proximity fed by a 50 micro-strip transmission line, acts as a main radiator while z-shaped slot acts as a filter for rejecting the full WLAN band (5.15-5.85 GHz). Use of an inverted T-shaped slot near top end of ground plane improves isolation more than 24.5 dB in lower UWB band i.e. 3-5 GHz, while the rectangular vertical slot etched at center of the ground plane near the bottom edge reduces the mutual coupling at lower as well as at higher UWB band i.e. 5 -10.6 GHz. Both measured and simulated results are presented which are found generally in good agreement.INDEX TERMS UWB, isolation, ultra-wide band (UWB), MIMO, WLAN, transmission line, FR4.

High-Isolation UWB MIMO Antenna with Multiple X-Shaped Stubs Loaded between Ground Planes

“…Reference [19] loads an inverted T-slot at the top of the center of the common ground plane of two rectangular antenna elements so that the isolation of the antenna is maintained above 24.5 dB within 3-5 GHz. Loading a vertical rectangular slot near the bottom of the ground plane reduces the isolation of the antenna in the range of 5-10.6 GHz and keeps the isolation of the antenna above 20 dB within 3.1-10.6 GHz.…”

Miniaturized MIMO Antenna with Low Inter-radiator Transmittance and Band Rejection Features

“…Various techniques have been used to reduce mutual coupling, such as decupling stubs, electromagnetic band gaps (EBG), split ring resonators, LC resonance, and suspended lines [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

“…Kumar et al [16] designed an octagonal-shaped MIMO antenna with dual-stop bands; the dimension of the antenna was 19 mm × 30 mm × 0.8 mm, isolation was greater than 18 dB and the ECC was less than 0.13 [16]. Chattha et al [17] designed a MIMO antenna with a dimension of 23 mm × 26 mm × 0.8 mm with a single-stopped band of WLAN; the isolation was greater than 20 dB and the ECC was less than 0.06. In the study by Babu and Anuradha [18], the authors designed a large rectangular antenna with the dimensions 60 mm × 35 mm, a transmission coefficient less than -16.53 dB and an ECC less than 0.04.…”

Dual-band-notched UWB MIMO antennas with miniaturization using half-cutting technology

“…In recent years, to address these issues, many researchers have studied the miniaturization technology [2][3][4][5][6], decoupling technology [7][8][9][10][11][12][13][14][15][16][17][18][19][20], and notch technology [1,16,19] of UWB MIMO antennas. The miniaturization technology mainly includes half-cutting technology [3,4], bending technology [5], and fractal technology [6].…”

“…The miniaturization technology mainly includes half-cutting technology [3,4], bending technology [5], and fractal technology [6]. The decoupling technology comprises a defective ground structure [7,8], reasonable layout of antenna elements (orthogonal placement [9][10][11][12] and inverted placement [7]), floor decoupling stubs [13,14,16], neutralization line technology [17], electromagnetic metamaterials [18], etc. Similarly, the notch technology contains etching slots [1,16], loading electromagnetic band-gap structure [4], embedding parasitic resonance structure [19,20], and so on.…”