公式推导，级数反演法，二维频域→方位频域距离时域

这是一个二维频域的相位表达式，变量为fa,fr：
phasefafr = (-((4 fc k0 \[Pi])/c) + (c (fa + (2 fc k1)/c)^2 \[Pi])/(
4 fc k2) + ((c fa + 2 fc k1)^3 k3 \[Pi])/(
16 c fc^2 k2^3) - ((c fa + 2 fc k1)^4 (-9 k3^2 + 4 k2 k4) \[Pi])/(
256 c fc^3 k2^5) + ((c fa + 2 fc k1)^5 (27 k3^3 - 24 k2 k3 k4 +
4 k2^2 k5) \[Pi])/(
1024 c fc^4 k2^7)) + (-((4 k0 \[Pi])/
c) - ((c fa - 2 fc k1) (c fa + 2 fc k1) \[Pi])/(
4 c fc^2 k2) - ((c fa - fc k1) (c fa + 2 fc k1)^2 k3 \[Pi])/(
8 c fc^3 k2^3) + ((3 c fa - 2 fc k1) (c fa +
2 fc k1)^3 (-9 k3^2 + 4 k2 k4) \[Pi])/(
256 c fc^4 k2^5) - ((2 c fa - fc k1) (c fa +
2 fc k1)^4 (27 k3^3 - 24 k2 k3 k4 + 4 k2^2 k5) \[Pi])/(
512 c fc^5 k2^7)) fr + ((c fa^2 \[Pi])/(4 fc^3 k2) + (
3 c fa^2 (c fa + 2 fc k1) k3 \[Pi])/(16 fc^4 k2^3) - (
3 c fa^2 (c fa + 2 fc k1)^2 (-9 k3^2 + 4 k2 k4) \[Pi])/(
128 fc^5 k2^5) + (
5 c fa^2 (c fa + 2 fc k1)^3 (27 k3^3 - 24 k2 k3 k4 +
4 k2^2 k5) \[Pi])/(512 fc^6 k2^7) - \[Pi]/
Kr) fr^2 + (-((c fa^2 \[Pi])/(4 fc^4 k2)) - (
c (2 c fa^3 + 3 fa^2 fc k1) k3 \[Pi])/(8 fc^5 k2^3) + (
c (c fa + 2 fc k1) (5 c fa^3 + 6 fa^2 fc k1) (-9 k3^2 +
4 k2 k4) \[Pi])/(128 fc^6 k2^5) - (
5 c (c fa + 2 fc k1)^2 (c fa^3 + fa^2 fc k1) (27 k3^3 -
24 k2 k3 k4 + 4 k2^2 k5) \[Pi])/(256 fc^7 k2^7)) fr^3
现在我希望用InverseSeries和Series即级数反演法将该相位表达书转到频域-时域（fa,tr)，我该怎么做？求大佬帮助