#### dd2023

##### Newbie level 4

I've embarked on a comprehensive study involving the simulation of broadband propagation of helical antenna impedances through a segmented transmission line (TL) impedance transformer. My goal has been to achieve the best possible impedance match over the broadest frequency range. The simulation involves multiple independent TL segments, each having a variable characteristic impedance (Zo).

**Observation**:Rather intriguingly, whenever I employ optimization methods to determine the ideal Zo for each segment, the results predominantly converge to sharp high-low transitions of Zo values, contrary to my initial expectation of a more smooth, continuous transition akin to the theory of small reflections.

**Queries**:

**Nature of Helical Antennas**: Could the intrinsic broadband behavior of helical antennas, with potential sharp impedance variations, be more inclined towards benefiting from distinct high/low impedance steps instead of a linear transition?**Impedance Transformation Dynamics**: For broadband impedance matching, is there a possibility that certain frequency ranges are more efficiently matched using stark impedance transitions rather than gradual ones?**Potential Resonant Behavior**: Might these high-low transitions be introducing a form of resonant impedance transformation across the broadband range, thereby being more effective than a simple gradient?**Discreteness and Optimization**: Given the discrete nature of assigning characteristic impedances to each TL segment, could the optimization be naturally predisposed to favor sharper transitions as a more direct path to the desired broadband impedance match?**Optimization Parameters**: I've primarily oriented my optimization to minimize reflections and maximize power transfer across the bandwidth. Could the objective function be inherently biasing the solutions towards these sharp transitions?**Solver Considerations**: How critical might solver settings and model fidelity be in driving the results towards high/low Zo transitions, especially given potential non-linearities or intricate interactions within the broadband spectrum?

Warm regards,

DD