Design of Tunable Monopole Arm Planar Spiral Antenna for Cognitive Radio

Table 3

Resonated frequencies for different diode ON-OFF conditions in ground plane.

Diode ON	Diode OFF	Resonant frequencies (GHz); Selective band/wideband
D1	D2, D3	{1.89, 2.63, 3.23, 3.66, 3.82, 4, 4.38, 4.99, 5.28, 5.64}/{6.15–10}
D1, D2	D3	{1.89, 2.38, 2.63, 3.28, 3.42, 3.66, 3.84, 4, 4.39, 4.98, 5.32, 5.64}/{6.15–10}
D1, D2, D3	—	{1.19, 1.72, 2.15, 2.33, 2.62, 3.26, 3.66, 3.85, 4, 4.42, 4.97, 5.33, 5.63}/{6.13–10}