Wideband microstrip antennas with sandwich substrate

A broadband microstrip antenna with low?high?low (sandwich) dielectric constant substrate combination using a microstrip line-via feed is presented for ultra-wideband applications. The proposed antenna consists of three dielectric substrates; low dielectric constant substrates that contain the microstrip feed line as well as parasitic patches and a high dielectric constant substrate that contains the driven patch. To achieve a large impedance bandwidth, parasitic patches and microstrip line-via combination feed to the driven patch in the multilayered microstrip antenna are used. The proposed antenna designed, fabricated and measured on the sandwich substrate. The antenna has measured 10 dB return loss bandwidth of 46.9% and directive gain .5.2 dBi at boresight across the impedance bandwidth. The total height of antenna is 5.77 mm or 0.077λ ^{at 4 GHz.}