以BST为介质基片的电调谐微带天线研究

An Electronically Tunable Microstrip Antenna Based on BST Substrate

在电子侦察和电子对抗领域的快速发展过程中,人们逐渐需要有性能优良的高速电调谐天线出现。制备了适合电调谐用途的钛酸锶钡(Barium Strontium Titanate,BST)铁电体,并分别在低频和微波频段下测量了其电磁特性。采用BST材料作为缝隙耦合微带天线的辐射层介质基片,利用其介电常数随外加偏压改变的性质,设计了以BST为介质基片的电调谐微带天线,并采用时域有限差分法(FDTD)进行了数值仿真,发现在一定偏压下天线的调谐性在C波段达到17%,方向图和阻抗的性能保持不变。

High speed electronically tunable microstrlp antenna whose resonance frequency can be controlled by DC voltage agilely is required in electronic surveillance and countermeasure. When Barium Strontium Titanate （BST）, one kind of ferroelectric material, is in paraelectric state, its dielectric constant is a function of the DC voltage on it. The BST was prepared and its dielectric constant and Tangent Loss were measured in low frequency and in microwave. Using this property, an electronically tunable aperture coupled microstrip antenna was designed whose ra- diant substrate was fabricated by BST. The design and the FDTD analysis of aperture coupled microstrip antenna were presented. The result shows that the antenna＇s tunable range is 17% at C band when the relative dielectric constant is changed from 70 to 50, while the impedance matching and radiation pattern remain good.