Ref Frequency Material Technique Bandwidth Size (mm)
[24] 3.5 FR-4 Open-circuit coupled line and capacitor unit cell 550 70 × 73.7
[27] 2.4 Rogers 4003C Circularly polarized (CP) 900 170 × 170
[37] 2.44 FR-4 Without crossover 200 96 × 96
[38] 2.5 FR-4 Open-stub and removal crossover 200 115.18 × 64.4
[39] 2.5 FR-4 Two section branch line coupler 400 120 × 150
[40] 1.8 ARLON Composite right/left handed CRLH-TL 200 109 × 119
[41] 6 Roger 4003C Mushroom-like 2300 100 ×110
[42] 0.86 RT/duroid 5880 double spiral lines (SDSLs) 150 109.0 × 89.3
[43] 2.4 Plastic complimentary square split ring resonators (CS-SRRs) 300 154 × 117
This work 2023
3.5
RT/5880LZ
Triangular slot and T-shape
836
85.5 × 75