Hybrid Utilization of Loading Techniques and Cavity Groove for Performance Enhancement of the UWB (2–18 GHz) Spiral Antenna

Table 1

Comparison of the proposed antenna with literature.

Ref.	BW (GHz)	VSWR	Gain (dBi)	Axial ratio (max. dB)	Size (mm)
[8]	2 to 18	<1.5 : 1	−6	7	56 dia.
[9]	2 to 18	—	−2	3.5	52 × 52
[10]	2 to 10	—	0	2	72 dia.
[11]	2 to 18	<2 : 1	−5	5 to 9	130 × 130
[12]	2 to 18	3.9–12.6	1.5	>5	60 × 60
[13] (without hybrid techniques)	2 to 18	<1.2 : 1	−4.9	2.6	50 dia.
This work	2 to 18	<1.8 : 1	>−2.65	2.27	50 dia.