This chapter presents some ideas and performance results for antennas that are variations on the monopole. Some will contain coils, and so will look like loop variations, but they have an open end at which the current must be zero. Loop variations are presented in the next chapter. The things that can be done to improve a monopole performance for a given space and operating wavelength are:
1. Make it thicker.
2. Increase its capacitance by top loading.
(a) Disc or radial wires.
(b) Volume loading.
3. Make it resonant
(a) by adding an inductor at the base or higher up,
(b) by making it with enough wire wound in the available space to make it λ/4,
(c) by making the radiating element a coil ...