An Isolation Improvement for Closely Spaced MIMO Antenna Using λ/4 Distance for WLAN Applications

Table 3

Comparison of the proposed antenna with an existing published antenna.

References	Dimensions (mm^3)/material	Isolation levels (dB)	Gain (dBi)	Radiation efficiencies	E.C.C	D.G (dB)	No. of ports	Applications
[7]	60.2 × 60.2 × 1.6/FR-4	≥−25 dB at 2.45 GHz	2.2	81%	≤0.1	9.94	4	WLAN
[8]	80 × 80 × 0.76/Rogers 4350B	>10 at 2.4–2.8	>1.7	>67	<0.1	NG	8	WLAN
[10]	100 × 50 × 0.8/FR-4	≥−18 dB at 2.4∼2.5 GHz	0.8	29%	≤0.3	9.53	4	I.S.M
[13]	30 × 65 × 1/FR-4	≥−15 dB at 2.4∼2.5 GHz	2.1	81%	≤0.006	9.8	2	WLAN USB dongle
[16]	90 × 50 × 0.8/FR-4	≥−47 dB at 2.3∼2.4 GHz	1.99∼2.78	48.43∼73.1%	≤0.0056∼0.110	9.42∼9.97	4	WiMax
[20]	95 × 95 × 2.284/Rogers RO4350 B	≥−25 dB at 2.395∼2.42 GHz	5.12	56.57%	NG	NG/NG	4	ISM
[21]	18.5 × 18.5 × 1.27/Rogers 6010LM	−15.99 at 2.4–2.48	−15.18	NG	0.0025	NG	4	Implantable
[22]	20.5 × 20.5 × 1.6/FR4	−32 at 2.45 GHz	2.6	55.44%	0.0081	NG	4	NG
[23]	119 × 119 × 22.5/Rogers RO4003, RO4450 B	≥−42 dB at 2.395–2.45 GHz	NG	NG/NG	<0.02	9.89	4	ISM
[26]	112 × 55 × 1.6/FR-4	≥−15 dB at 2.4 ∼2.48 GHz	NG	66∼75%	0.23∼0.13	9.73∼9.99	2	I.S.M
[27]	72.4 × 20 × 0.8/Rogers RO4350 B	≥−27.6 dB at 2.18 ∼2.65 GHz	1.39	66∼70.5%	0.08∼0.09	9.96∼9.95	2	I.S.M
[29]	80 × 80 × 01.6/FR-4 substrate	∼20 dB at 2.5 GHz	NG	NG	0.054	9.68	2	LTE
[32]	140 × 120 × 1.5/FR4	−20 at 2.4–2.4835	NG	NG	<0.1	NG	4	WLAN
[38]	34 × 18 × 1.6/FR4	−15 at 2.45 GHz	1.26	76	0.12	NG	4	LTE 2300 and I.S.M
Proposed antenna	45.5 × 45.5 × 1.96/FR4	−58.37 at 2.4 GHz	2.84	90	0.0054	10	4	ISM

Bold indicates proposed antenna’s parametrical values.