RF PCB design: right angles in components?
Strictly speaking, the AC signal current through the capacitor is exactly the same current as if the capacitor was bridged - this means it acts just like you'd expect a right angle pcb trace to act but, don't beat your self up on this  - at 1GHz maximum it's not a major problem. The problem occurs when you have the track folding back on itself and forming a capacitor and an inductor - this forms a parallel tuned circuit in series with the signal and can lead to anomalies but, at 1GHz this isn't going to be significant.

Try calculating the effective inductance of the trace round the corner and the capacitance formed - this will be well above 1GHz.