Design and Implementation of a Miniature X-Band Edge-Coupled Microstrip BPF Using AWR Software
3 www.cadence.com/go/awr
The widths, spaces, and lengths of the coupled line were calculated with the TX-LINE calculator within the AWR Design
Environment. An equivalent circuit was developed for derivation of the design equations for the BPF using admittance
parameter equations from Pozer [1]. Figure 2 shows the layout of (a) an N+1 section coupled line BPF, (b) equivalent circuit for
each coupled line section, and (c) the equivalent circuit for transmission lines with a length of 2q. Figure 3 shows (d) the
equivalent circuit for the admittance inverter, (e) the results of (c) above and (d) for the N = 2 case, and (f) the lumped-el-
ement circuit for the BPF for N = 2.
Figure 2: Development of an equivalent circuit for derivation of design equations for the BPF.
Figure 3: The equivalent circuit for the admittance inverters.
The coupled filter design equations are as follows:
1187 . 0
0967 . 1 5963 . 1
1
2
1 . 0 1
2
'
2 1
2 , 1
=
´
´
´
= ´
W
=
p p
g g
J
1187 . 0
5963 . 1 0967 . 1
1
2
1 . 0 1
2
'
3 2
3 , 2
=
´
´
´
= ´
W
=
p p
g g
J
B
B
[ ]
W = + + = = 64 . 56 1187 . 0 1187 . 0 1 50 , ,
2
3 , 2 2 , 1 oe oe
Z Z
[ ]
W = + - = = 77 . 44 1187 . 0 1187 . 0 1 50
2
3 , 2 , 2 , 1 , oo oo
Z Z
D
E
!
"
/4=
3×10
*
2, -
"
=
3×10
*
4×9×10
/
3.55
=0.017674
The required resonator
