If you're thinking about a multi-band inverted-L then you might consider the G7FEK which is basically a 'fan inverted-L' or multiple inverted-L's fed from the same feed point. I'd use an actual radial system rather than the single counterpoise wire shown by G7FEK but it's a compact multi-band inverted-L. http://www.sral.fi/turva/G7FEKantenna.pdf https://www.g8jnj.net/G7FEK antenna revisited.pdf