Leaky wave antennas (LWAs) have been experimentally demonstrated in recent years as a promising candidate for THz-scale networking. They operate on the principle of angular dispersion, where higher frequencies radiate with maximum power towards smaller angles. These devices offer frequency support upto 1 THz, where this coupling has enabled dynamic beam steering through frequency tuning and path discovery. Obtaining these benefits at both the transmitter and receiver requires deploying LWAs at both nodes. However, in such a link, since angular dispersion affects both transmission and reception, a given frequency is maximally coupled out of the transmitter and into the receiver only if the emission and reception angles are equal.

In this work, we perform the first performance evaluation of angularly misaligned THz LWA-LWA links, utilizing a mix of numerical studies and over the air experiments, with the following key contributions. We first introduce a numerical model yielding data rate in a LWA link, capturing how the fall in data rate arising from coupling loss due to misalignment is not only angle dependent, but is non-linearly dependent on both frequency and bandwidth. Using this model, we perform the first numerical study to quantify the rate and coverage penalty of angularly mismatched LWA links, demonstrating the tradeoff that the link is more robust to misalignment at large emission angles, but has access to lower data rates, and that perfect alignment does not maximize data rate. We next evaluate the performance of using both multiple angularly separated LWA slots per sector, and opportunistically utilizing non line of sight (NLoS) paths as a means of obtaining multiple options in emission and reception angles, to overcome the rate loss due to misalignment. We show that the higher the emission angle, the fewer the number of slots required to overcome mismatch to a given extent, and that the average rate achievable with N+1 additional NLoS paths is comparable to that attainable with N additional slots. Finally, we perform the first experimental study of the performance of angularly mismatched THz LWA links, where we show that as compared to the numerical model, not only is data rate maximized with even greater misalignment, but that the experimental link is far more robust to angular mismatch.