With this type of feed, impedance transformation to a useful value is needed as the impedance near the edge of the patch is quite high (a couple hundred Ω typical).
The advantage of this structure is the ability to place circuitry near the elements on the same substrate and avoid a multi-layer board. Also, elements can be connected in parallel in the same plane to form an array.
The impedance transformer itself tends to radiate and may distort the radiation pattern of the antenna.
A nice solution is a combination of the antennas from Figures 11 and 12 and shown in
Figure 13.