Compact Shared-Aperture Slot/DR Antenna With Large Frequency Ratio

A compact shared-aperture antenna with a large frequency ratio is proposed. It consists of a low-frequency (LF) slot antenna and a high-frequency (HF) dielectric resonator antenna (DRA). The LF slot antenna is etched in the ground and loaded by the HF DRA. It employs a low-permittivity substrate, thus giving a wide bandwidth. The HF DRA is excited by a dual-microstripline-fed slot. The operating frequencies of these two antenna parts can be tuned independently. A prototype is fabricated and measured to verify the simulation. It has a very compact electrical size of 0.27 × 0.08 × 0.03λ
$_{0}^{3}$
, where λ
₀
is the wavelength in air at the center frequency of the LF band. Its measured frequency ratio is 7.6, with reasonable agreement between the measured and simulated results.