Optimal power-aperture balance

The radar system designer is constrained by limited budgets for resources such as cost, weight, prime power, and volume. Under these constraints, the designer attempts to maximize the radar system performance. After selecting the operating frequency band and the basic design approach, the primary way to improve radar performance is to increase the average radiated power (P) and the antenna aperture area (A). Search radar performance scales with the power-aperture product PA, track radar performance scales in proportion to PA², and fire control radar performance scales as PA³ of PA⁴. After allocating resources to all other sub-systems (e.g. computers and signal processors), the system designer must determine how to balance resource allocation between P and A. This analysis determines the optimal allocation of the critical resource that is exhausted before others. If the resource cost of P and A are linear and independent, the analysis shows that for a search radar the critical resource should be divided equally between P and A. For a track radar, one-third of the critical resource should be allocated to P and two-thirds to A. For a fire control radar, one-fourth or one-fifth of the critical resource should be allocated to P, with the remainder allocated to A. The analysis also provides results to optimally balance P and A in the case where the resource costs are non-linear functions. The appendix reviews the relationship between P, A, and radar performance.