a quantitative description for the performance of our proposed scheme summarized in Table \[table:power\]. It shows the average power calculated in dB received at the tumor region $\Omega_T$ and at the healthy region $\Omega_S$.

         Scenarios         $\Omega_T$   $\Omega_S$
  ----------------------- ------------ ------------
     Nominal, $\R_{0}$      $-16.54$     $-29.78$
    Perturbed, $\R_{0}$     $-36.40$     $-11.69$
   Perturbed, $\R^\star$    $-27.17$     $-17.43$

  : Average power for different regions[]{data-label="table:power"}

Conclusion
==========

The robust transmit signal design for optimizing spatial power distribution of an multi-antenna array is investigated. A robustness analysis is carried out to combat against inevitable uncertainty in model parameters which results in performance degradation. Such degradation occurs in practice quite often due to relying on imperfect prior and designs based upon them. Particularly, in this paper, the transmit signal design is based on exploiting the waveform diversity property but where errors in the array steering vector are taken into account. These errors are modeled as belonging to a deterministic set defined by a weighted norm. Then, the resulting robust signal covariance optimization problem with infinite number of constraints is translated to a convex problem which can be solved efficiently, by using the $\mathcal{S}$-procedure.

Designs that are robust with respect to the worst case are particularly vital in biomedical applications 