扇形波导可作为高功率微波圆柱共形波导缝隙阵天线的基本单元。分析了扇形波导中主模场分量，根据实际情况对主模场进行了合理近似。采用互易定理推导由波导主模横向场分量和缝隙场分量表示的波导场分量的前向或后向散射系数。根据波导传输线理论，将波导宽边纵缝等效为并联导纳，再根据波导边界条件得到扇形波导宽边谐振纵缝的归一化电导与波导散射系数之间的关系式。根据缝隙天线与振子天线的互补关系得到扇形波导谐振缝隙的辐射阻抗，结合波导功率平衡关系得到由波导横向场散射系数表示的缝隙辐射功率表达式，得到归一化电导的与谐振宽边纵缝的偏移位置、缝隙宽度、波导波长以及扇形波导尺寸参数之间的解析表达式。给出了算例，在波导中间区域，通过商用软件计算得到的电导与理论公式结果基本吻合。

The sectorial waveguide can be used as an element of high power microwave(HPM) cylindrically conformal slotted waveguide array antenna. In this paper, the field components for the domination mode in a sectorial waveguide are investigated. According to the practicality applied area, the field components of domination mode can be reasonably approximated. By the reciprocity theorem, the amplitudes of forward or backward scattered mode can be expressed by the transverse field components of waveguide and the field components in slot. By the transmission line theorem, the longitudinal shunt slot is equivalent to a shunt obstacle on a two-wire transmission line. According to the boundary condition, the resonant normalized conductance of the slot is expressed by the amplitudes of scattered domination mode. The radiation resistance of half wavelength slot is obtained from the complementary half wavelength dipole. The amplitudes of scattered domination mode are expressed by radiation power of slot. The analytic formula of the resonant conductance for longitudinal shunt slots cut in the curved broad face of the waveguide is derived with the parameters of offset angle from the center line,the width of slot, the wavelength and guide wavelength and the dimension of inner cavity of waveguide. An example is presented and the result obtained in the middle area of waveguide is satisfactory.