The directors’ width, WD1 and WD2 are slightly shorter than
driven element width, WD around 5% and 10 % respectively.
While the reflector width, WR is 5% longer than the driven
element width. Through simulation, the length of reflector and
directors are designed to be about ¼ of their total width. The
dimensions of the optimization microstrip Yagi antenna for
both branches are shown in Table I.