How to input more than one Greek Letter on legend

I want to insert legend for more than one signal. This code only works for one and when I try to insert another legend it says unknown property. Also inserting symbols are not quite clear to me,what mistake am I making in title too. Since that theta is not showing up.

l = legend({'$\hat{\theta}(t)$'});

set(l,'interpreter','latex')

title('Estimated Signal {\theta} using Adaptive Oscillators')

xlabel('Time')

ylabel('Amplitude')