Compact and Broadband LPDA With Flat-Ended Bow-Tie Elements for TVWS Band

A compact and broadband Log-periodic dipole array antenna with bow-tie elements is proposed to achieve endfire radiation. The bow-tie elements are used for broadband frequency response and to decrease the size of the antenna in the lateral direction. To further reduce the lateral dimension, the largest dipole is folded to make a C-shaped dipole element. To reduce the size of the antenna along the boom length, the end elements are made flat on one side and triangular on the other side. The proposed LPDA antenna has a compact size of 0.32λL ×0.11λL and it provides 41.7% bandwidth for VSWR < 2, the peak gain of 4 dBi, and a better figure of merit.