A Low Profile Annular Ring Shorted Logarithmic Spiral Antenna offers Decade Bandwidth

A novel antenna in which the logarithmic spiral antenna (LSA) is shorted with an annular ring has been proposed. The electrical performance in terms of transmission and radiation characteristics of the proposed antenna is analyzed. A prototype is fabricated and characterized to establish concurrence between the qualitative analysis and experimental results. The proposed LSA has an impedance bandwidth of 0.4-4GHz for VSWR better than 2.5 and gain bandwidth of 0.6-4GHz for gain better than 3 dBi. An excellent correlation is observed between the simulation and measured results.