e new version of the Price’s algorithm given in Brachetti et al. [J. Global Optim. 10, 165–184 (1997)]. Its distinguishing features include: (1) The number-theoretic method is applied to generate the initial population so that the points in the initial population are uniformly scattered, and therefore the algorithm could explore uniformly the region of interest at the initial iteration; (2) The simplified quadratic approximation with the three best points is employed to improve the local search ability and the accuracy of the minimum function value, and to reduce greatly the computational overhead of the algorithm. Two sets of experiments are carried out to illustrate the efficiency of the number-theoretic method and the simplified quadratic model separately. The proposed algorithm has also been compared with the original one by solving a wide set of benchmark problems. Numerical results show that the proposed algorithm requires a smaller number of function evaluations and, in many cases, yields a smaller or more accurate minimum function value. The algorithm can also be used to deal with the medium size optimization problems.

A new reflector shaping technique to improve the beam scanning capability of hybrid antennas (i.e., a reflector system illuminated by a phased array) is presented. Errors between the desired scan directions and the outgoing rays’ directions in the scanning range are minimized by adjusting the reflector shape. This technique can be used to decrease the active element number of the feed array during the antenna scans, or reduce the gain loss caused by beam scanning when the number of active elements is given. An offset reflector antenna system is designed and analyzed, through which the validity of the technique is demonstrated.

A novel reconfigurable coplanar waveguide (CPW)-fed square slot antenna with switchable polarization is presented. The proposed antenna is fed by a CPW, with two T-shaped metal strips connected to ground plane using pin-diodes. Switching between right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) is achieved by turning the pin-diodes on or off. The designed antenna is implemented and measured. It shows that the proposed antenna has broad CP bandwidth in both RHCP and LHCP states.

A novel small CPW-fed T-shaped antenna for MIMO application is presented. The size of the antenna is only 35% of that of conventional CPW-fed T-shaped antenna, which has satisfied return loss bandwidth and omnidirectional radiation characteristics. A multifeed 8-element planar array is fabricated and measured. It shows that the features of small size, uniplanar structure, good radiation characteristics and small mutual coupling are promising for MIMO applications in compact portable devices.

The application of the new nonlinear optimization algorithms to arrays design is demonstrated by the low-side-lobe pattern synthesis of conformal arrays. By adopting the information of array element realized gain patterns (RGP’s), we formulate synthesis problems as nonlinearly constrained optimization problems, and propose a new direct method to solve them. The technique allows one to find a new direct method to solve them. The technique allows one to find a set of array coefficients that yield a pattern meeting a specified side-lobe level and achieving the maximum directivity, if such a set of array coefficients exists. If the side-lobe specifications cannot be met with the given array, the technique will result in a set of coefficients that yield a pattern meeting the best attainable side-lobe level and having directivity as high as possible. Also, simplified synthesis problems for an axial dipole array in an infinite, perfectly conducting cylinder are discussed, and numerical synthesis results are given. Our synthesis technique works for general array patterns.