| 摘要 |
A dual-port IBOC® antenna provides omnidirectional radiation of orthogonal, circularly polarized analog (FM) and digital (OFDM) signals using quadruple coplanar square loops driven from a hybrid having balanced outputs. The loops are arranged in a tiled square, with proximal sides functioning as further stripline hybrids to cancel cross coupling between the loops. Each loop quad is reflector-backed and emits a directional signal; multiple loop quads oriented radially form an omni bay. Vertical spacing between bays includes a minimum position for mutual coupling, while symmetry establishes uniform input impedance on the hybrid input ports. Tuning barbs on the loops fine tune frequency response. Bandwidth is wide, so that a single antenna can radiate multiple FM analog and hybrid IBOC® channels over the VHF FM radio broadcast band. |
