Is $Q(b)=a^Hb+b^Ha$ ,where $a,b \in \mathbb{C}^{N\times1},b^Hb\leq\epsilon^2$convex or concave?

Question

We assume that $a,b \in \mathbb{C}^{N\times1},b^Hb\leq\epsilon^2$. Is the function $Q(b)=a^Hb+b^Ha$ convex,concave? In other words, which of the following problems is feasible?

$\min\ \ a^Hb+b^Ha \\ s.t.\ \ \ b^Hb\leq\epsilon^2$

or

$\max\ \ a^Hb+b^Ha \\ s.t.\ \ \ b^Hb\leq\epsilon^2$