Here is my cvx code
cvx_begin
variable x(para.M,1) complex
minimize real(x’d_bo) %23a
subject to
for k=1:2para.K
hhh=h_i(:,k);
real((hhh)’*x)>=beita; %23b
end
for kk1=1:para.M
abs(x(kk1))<=sqrt(para.Pt/para.M); %23c
end
cvx_end

Thank you for your help.And then I have another question.
Here is my cvx code
cvx_begin
variable x(para.M,1) complex
minimize real(x’d_bo) %23a
subject to
for k=1:2para.K
hhh=h_i(:,k);
real((hhh)‘x)>=beita; %23b
end
for kk1=1:para.M
abs(x(kk1))<=sqrt(para.Pt/para.M); %23c
end
norm(xx’-R)<=0.5;
cvx_end

Expanding on @Erling’s comment, that is the matrix (operator) two norm (of a matrix argument). I.e., maximum singular value of (x*x'-R ) <= 0.5. That would be a convex constraint, and allowed in CVX, if the matrix argument were affine, which as @Erling pointed out, it is not. If that is the constraint you really want, it is non-convex. But is that really the constraint you want?