The invention belongs to a circular-arc
microstrip curve plane slow wave device which is assorted with a travelling
wave tube in a
microwave vacuum electronic technology. The circular-arc
microstrip curve plane slow wave device comprises a
boron nitride substrate, a semicircular
microstrip curve and a
metal shell, wherein the semicircular microstrip curve is fixed on the substrate and has an input end and an output end. According to the invention, because the microstrip curve the connection part of which is a smooth semicircular-arc is adopted, and
boron nitride which has low
dielectric constant and higher compression strength,
hardness and heat
conductivity factor is used as the substrate, not only the
coupling impedance and the output power are improved, but also the strength and the heat dissipation of the substrate as well as the finished product ratio and the service life in the production process of the slow wave device are effectively improved. Therefore, the microstrip curve plane slow wave device can work in a
frequency band above
millimeter waves stably and reliability at the same time of being miniaturized and has the characteristics of good heat dissipation and high
coupling impedance and output power, high performance and reliability while cooperatively used with the travelling tube working in a
frequency band above
millimeter waves, as well as high finished product rate and long service life in the production process of the slow wave device, and the like.