Compact Self-Decoupling Cylindrical Pattern-Diversity Dielectric Resonator Antenna

In this letter, a compact self-decoupling cylindrical pattern-diversity dielectric resonator antenna (DRA) is proposed. This design adopts shared coupling slot technology and leverages the cancellation characteristics of coupling current between the common mode (CM) and differential mode (DM), resulting in a significant improvement in isolation between the two ports. Additionally, the design employs CM current to excite the HEM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_δ</i> mode at the center of the coupling slot, producing a boresight radiation pattern. On both sides of the coupling slot, DM current is used to excite the TE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_δ</i> mode, yielding an omnidirectional radiation pattern. This innovative shared-slotline design allows for the excitation of two modes with distinct radiation characteristics using a single slot. To ensure that both modes resonate at the same frequency, the design utilizes the difference in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i>-field strength at the bottom of the DRA: the HEM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_δ</i> mode exhibits the strongest <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i>-field, while the TE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub><italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_δ</i> mode shows the weakest. By reducing the dielectric constant around the bottom region of the DRA, it achieves resonance at the same frequency for both modes, enabling the diversity design. To verify the simulation results, a self-decoupling pattern-diversity DRA prototype for 5.2 GHz WLAN application is manufactured and measured. The measurement results demonstrate that the antenna achieves an isolation of higher than 39 dB and an envelope correlation coefficient (ECC) below 0.1 across the 5.2 GHz band.