Implementation of a Dual-band and Miniaturized Log-Periodic Dipole Antenna loaded by ENG Cells

Miniaturized dual-band microstrip Log-Periodic Dipole Array (LPDA) loaded by reactive cells is studied. These cells are implemented by two rake-shaped resonators. Such a reactive cell is analyzed and it is shown that its unit cell has a f-Negative (ENG) performance. By loading such cells on an LPDA consists of two dipole elements, it is revealed that such an antenna performs in two separate frequency ranges. The added working frequencies due to loading effect are lower than the frequencies of the unloaded LPDA. The radiation efficiency of ENG-loaded LPDA in lower resonant is high. Validation of the numerical results is carried out by manufacturing a prototype of the loaded LPDA and successfully testing it. The measurements have a good agreement with those obtained by simulations. It is experimentally indicated miniaturized LPDA has a dual-band performance while its conventional bandwidth is broaden.