I see, thanks for the clear answer. Yes, my goal is to increase gain horizontally, so it appears to be the right approach. Naturally, if the radiated energy is the same, the spatial distribuition would need to be arranged differently. And now that I think about it, there are various high-gain wifi antennae on the market advertising a gain well above 10 dB, which are all reported to increase reception quality perpendicular to the whip.
PS1: If I wanted to learn a bit about antenna theory, what literature would you recommend for a beginner? This subject seems interesting.
(PS2: how is your trace antenna desing coming along?)