I came to know that a meandered inverted-F antenna (MIFA) can be used to reduce the size of a long antenna and it's often used in mobile phones to make the antenna smaller.
So, can MIFA be used to get SW reception for a radio receiver?
What is the method and formula to build the antenna?
Inverted-F antenna (IFA) is a variant of inverted L antenna that is already very common in MF and lower HF bands. IFA feeds through a tap instead of the end of the L-line to increase the feedpoint impedance, simplifying the matching circuit. MIFA is a zigzag-shaped folded version of IFA, as the name implies. MIFA is a compromise between the size and the performance, like any other antenna.
IFA and MIFA are commonly used in portable electronics (Bluetooth, Wifi, etc.) because they can be constructed as PCB patterns, lowering the assembly cost, but their performance is inferior to just a piece of wire cut to quarter-wavelength. Another advantage of IFA and MIFA is that their bandwidth and return loss are generally well studied, relatively easy to simulate, and the formulaic design templates are published.
There is no advantage of exactly constructing an IFA or MIFA for HF receivers. The ground structure/conductivity/permittivity is more variable than the ground plane on the PCB (although there is a big question when the portable electronic device is on the human body or a conductive desk.) After all, a simple inverted L would suffice.
