An Annular Ring Shorted Logarithmic Spiral Antenna with Planar Integrated Feed

A novel concept of overall lateral and normal dimensions reduction of a spiral antenna is described in this work. Specifically a combination of techniques that complement each other to achieve overall profile reduction is tried. A microstrip line that is integrated into the annular ring shorted logarithmic spiral is used as a feed to achieve size reduction. Extensive simulation based analysis is carried out to optimize the antenna. The optimized design is fabricated and measured. Simulation and measured results are discussed. Impedance and axial ratio bandwidth of 260.9% are achieved.