Patent ID: 8164535

Claim:
A coplanar waveguide (CPW) fed planar log-periodic antenna, comprising: an upper substrate; a planar log-periodic antenna structure formed beneath the upper substrate; a CPW-fed structure formed on the upper substrate for feeding energy into the planar log-periodic antenna structure; a lower substrate disposed beneath the upper substrate; and a wire structure formed beneath the lower substrate, wherein the CPW-fed structure comprises: a microstrip formed on the upper substrate with a width increasing towards two edges of the upper substrate, wherein the microstrip comprises: a signal transmission region with a width increasing towards two edges of the upper substrate, wherein a first dielectric region, a second dielectric region and a third dielectric region are formed around the signal transmission region, in which the first dielectric region and the second dielectric region extend towards two edges of the upper substrate and form an angle with the third dielectric region, and with a fourth dielectric region and a fifth dielectric region formed at locations spaced out a specific distance apart from the first dielectric region and the second dielectric region respectively, with the fourth and fifth dielectric regions extending towards two edges of the upper substrate; and a signal ground region formed outside the signal transmission region and the first to fifth dielectric regions; and through holes vertically formed in the upper substrate and connected to the microstrip and the planar log-periodic antenna structure, wherein the through holes comprise: a first feed through hole vertically formed in the upper substrate and connected to the signal transmission region and the planar log-periodic antenna structure; and a second feed through hole vertically formed in the upper substrate and connected to the signal ground region and the planar log-periodic antenna structure.