Wide-frequency-range tuned helical antennas and circuits

Synthesis of unequally spaced arrays using dynamic programming

“…However, calculations show that the assumption leads to results which are reliable. In the case of the 9-element array, the best design obtained by the dynamic programming technique coincides exactly with that obtained by trying all possible combinations [4], and several other combinations investigated by this technique yield sidelobe levels that are not appreciably Merent. For the larger array considered here, verification by total enumeration is not feasible, but the preliminary hdings on the 9-element array are otherwise fully substantiated and it seems reasonable to assume that the results obtained are quite close to being truly optimum, if not themselves so.…”

“…On reapplying the dynamic programming method with slight modifications to the 9-element array previously considered by Skolnik et al [3], Nath and Arora [4] reported that this method did in fact lead to truly optimum designs for that particular array, as was verified by considering all possible combinations of elements. It was assumed, though it could not be justified in a rigorous way, that the principle of optimality was applicable to this problem.…”

Optimizing the Secondary Coil of a Tesla Transformer to Improve Spectral Purity

“…Maximum energy transfer to the load is obtained during the second half-cycle of the oscillatory response that follows the application of a voltage step to the primary circuit when the spark gap in the primary circuit is triggered. Quite separately, helical cavity filters [7] are high-Q devices similar to coaxial lines with helical inner conductors; they are used in radio frequency applications [8] such as filtering radio receiver inputs [9], or transmitter outputs of cellular phone base stations [10] [11]. Although their application to high power pulse generation is not immediately obvious, a striking similarity exists between the geometry of a helical filter and the secondary coil of a Tesla transformer.…”