Design of a T-shaped Slot Structure for Increasing Isolation Between Two Nearby Microstrip-fed PIFAs
|關鍵字:||多輸入多輸出系統;分集技術;隔離度;T型狹縫;微帶線-狹縫轉接;MIMO system;Diversity technology;Isolation;T-shaped slotline;Microstrip-to-slotline Transition|
A novel isolation structure based on a T-shaped slotline junction for use with diversity-capable wireless communication systems is presented. The entire circuit consists of two microstrip-fed PIFAs, a T-shaped slotline junction, and two microstrip-to-slotline transitions. For reducing the dimensions of PIFA, the typically straight open-ended transmission line is turned into a spiral such that it is more compact and practical for the wireless mobile devices. Because the intense correlation due to mutual coupling between two nearby PIFAs, we design a T-shaped slotline junction-based isolation enhancement structure to suppress the coupling effect. Moreover, the microstrip-to-slotline transitions provide the coupling of energy between PIFAs and T-shaped slotline structure. Finally, the simulated and measured results prove that T-shaped slotline structure increases the isolation without affecting the impedance matching of PIFAs. Furthermore, as expected, the radiation patterns and peak gain vary slightly as the current distribution is changed by the T-shaped slotline structure on the ground plane. Good agreements observed between theoretical and measured results confirm the validity of the proposed design in this thesis.