The revolution of true SMT circulators
Typically, incorporating circulators into a PCB design involves cut-outs prior to installation, to provide a better mechanical stability for the bulky component. During assembly, a circulator is normally screwed down and soldered. This level of hand assembly, and the additional assembly components and stages, comes with added risks and costs. For example, while soldering, the hot iron can induce excessive heat, ultimately damaging the magnetic circuit of the circulator. Rough handling of a circulator or isolator can also affect the device performance.
With hand assembly eliminated from the process, and with high precision automation replacing it, these added costs and failure points could be eliminated. In order to reduce the design considerations and failure rates with less human error, a true surface mount technology (SMT) circulator with comparable performance to prior technologies would be necessary. Hence, Smiths Interconnect's TRAK Microwave brand's efforts and investment in developing a true SMT X-band circulator with adequate isolation, insertion loss, and power handling to replace prior circulator technology.
Though there has been some headway in semiconductor-based active SMT circulators on chip, the performance of these devices has yet to approach what is necessary to meet mission critical performance expectations. TRAK’s ferrite-based true SMT circulator maintains a passive non-reciprocal behavior, as opposed to recent active SMT circulators. These active devices emulate ferrite EM radiation manipulation, but function without ferrites, so require external biasing or external matching network. Thus, these active devices add design restrictions and considerations, and offer limited bandwidths and isolation. With North America dominating the growth in the X-band radar market, X-band SMT circulators have more practical uses than ever with automation, accessibility, and a tune-free/hassle-free design.