The present subject matter relates to antenna systems, devices, and methods that provide efficient coverage of low frequency bands (e.g., 700 MHz-bands and 600 MHz-bands) for the new generations of mobile communication. For example, a dual-resonant radiating system can include a ground plane, a radiating coupler spaced apart from but in communication with the ground plane, and a ground plane extension in communication with the ground plane. In this arrangement, one or both of the radiating coupler and the ground plane extension are tunable to tune a dual-resonance frequency response.