Design of Tunable Monopole Arm Planar Spiral Antenna for Cognitive Radio

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<g transform="matrix(.012,-0,0,-.012,8.225,15.475)"><path d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" id="x31"></path></g><g transform="matrix(.012,-0,0,-.012,13.936,15.475)"><path d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" id="x31"></path></g>
</svg> (a) at D1 condition (b) at D1 + D2 condition.</table>

Advances in Electrical Engineering

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Figure 13

Figure 13: Design of Tunable Monopole Arm Planar Spiral Antenna for Cognitive Radio 