A dosage form is disclosed comprising means for delaying the delivery of drug from the dosage form following the administration of the dosage form to a patient in need of drug therapy. A third variable capacitance element is connected between a second terminal of the balanced port of the balanced to unbalanced transformer and the second helical antenna element. In exemplary embodiments of the present invention, the number of multiplications is reduced by pre-computing certain values needed for the determination of the branch metric and storing these pre-computed values in a product table.