What happens to the bandwidth of an antenna as it is shortened using loading coils?

When an antenna is shortened using loading coils, the bandwidth of the antenna decreases. This occurs because loading coils effectively add inductance to the antenna system, which influences its resonant frequency and causes a narrower bandwidth. As the physical length of the antenna is reduced, the electrical characteristics change, leading to a less pronounced resonance peak and consequently a reduced ability to operate over a wide range of frequencies.

In essence, the relationship between the length of the antenna and its bandwidth is such that shortening the antenna results in a sharper resonate curve. This means the antenna becomes less versatile, functioning optimally only at specific frequencies rather than over a broader range. Thus, using loading coils not only modifies the resonant frequency but also compresses the operational bandwidth, making the shorter antenna more focused but less capable of handling multiple frequencies effectively.