An antenna system includes: a radiating element; a feed coupled to the radiating element at a first point on the radiating element and configured to convey energy to the radiating element; and a radiation-adjustment device coupled to the radiating element at a second point, configured to alter a radiation characteristic of the radiating element, and including: coarse-adjustment elements; an integrated-circuit chip including: switches, each coupled to a respective one of the coarse-adjustment elements where the coarse-adjustment elements are disposed external to the integrated-circuit chip; and a fine-adjustment circuit; the antenna system further including a controller communicatively coupled to the switches and to the fine-adjustment circuit, the controller configured to alter the radiation characteristic of the radiating element by selectively causing one or more of the switches to couple one or more of the coarse-adjustment elements to the radiating element, and by adjusting a value of the fine-adjustment circuit.