A Wideband Tightly Coupled Array for Omnidirectional Pattern Synthesis

Table 1

State of the art of TCAs.

BW	VSWR		Features	Ref
1.6:1	<2	93% (B.S.)	Shorted edge terminations	[6]
2.5:1	<2	N.M.	Parasitic ring loading	[7]
3:1	<2.1 (B.S.)	N.M.	PUMA	[8]
3.3:1	<3	N.M.	Octagonal ring element	[9]
5:1	<2.1 (B.S.)	N.M.	PUMA	[10]
5:1	<2 (B.S.)	N.M.		[11]
5:1		>60%	Metasurface
6:1	<3	85%	Capacitive overlaps	[12]
6.1:1	<3.2	65%–80%	Maximum scan angle; FSS superstrate	[13]
7.35:1	<2.65	N.M.		[14]
9:1	<3.4	N.M.	Resistive FSS	[15]
10:1	<2 (B.S.)	N.M.	Spiral element	[16]
13.5:1	<2.5 (B.S.)	60%–70%	Substrate loading	[17]
21:1	<3 (B.S.)	73%	Resistive FSS substrate	[18]

B.S.: broadside scan. N.M.: not mentioned. PUMA: planar ultrawideband modular antenna.