7. The minor axis of the ellipse $\rho=\frac{1}{2-\cos \theta}$ is equal to

保留了源文本的换行和格式。
$$
\frac{2 \sqrt{3}}{3}
$$
7. [Analysis and Solution] From $e=\frac{c}{a}=\frac{1}{2}, \rho=\frac{b^{2}}{c}=1$ and $b^{2}=a^{2}-c^{2}$, we get $b=\frac{\sqrt{3}}{3}$. Therefore, $2 b=\frac{2 \sqrt{3}}{3}$.