波导滤波器
-30
-40
S11 Measured
-50
S21 Measured S11 HFSS
S21 HFSS
S11 Goal
-60
S21 Goal
-40
-30
-20
-10
0
10
20
30
f -f0 (MHz)
g/2
0 jK
A j K
0
1 K2
2K
K12
S
Z10
mj
1
K 2 2K
mj
K23 1
K2 1
1ZK0 K2
K2
2
;
g/2 S11
S22
1 1
K 2 K 2
;
S21
S12
mj
2K 1 K2
Z0 K
K变换器计算模型
Z0A
K01 Z0
K12
Z0
K23 Z0
利用对称面g可/2 以简化模g/型2 ;
滤波器测试结果
Designed at 15.35 GHz Tunable from 14.9 to 15.35
GHz Measured at 15.32 GHz
S21 (dB)
S (dB)
0
-1
-2
-3
-4
-5
-6
15.29
15.3
15.31
15.32
15.33
15.34
15.35
frequency (GHz)
现代滤波器设计讲座(三)
腔体级联耦合波导滤波器
电子科技大学 贾宝富 博士
矩形波导滤波器常见类型
对称膜片 纵向条带
横向条带
方柱
圆柱
波导滤波器设计举例
设计参数: f0 = 15.35 GHz BW= 32 MHz S11 < -20 dB S21 < -40 dB @ f0 ± 40 MHz
滤波器从 14.9到 15.35 GHz连续可调
现代滤波器设计讲座(三)
波导滤波器设计
电子科技大学 贾宝富 博士
波导滤波器概述
波导滤波器具有插入损耗低、功率容量大和容易批量 生产的特点;
波导滤波器的工作频率可以达到毫米波波段。主要用 于卫星通讯、电子对抗和雷达系统。
波导滤波器有以下几种类型:
直接耦合波导滤波器; 交叉耦合波导滤波器; 带抑制谐振器的波导滤波器; 使用非谐振结点的波导滤波器; 使用过模谐振器的波导滤波器; 凋落模波导滤波器;
计算K值;
K 1 S11 1
计算附加相移;1 S11 S21
1 S21
2
1
i 90 argS21
Z0 Kn
优化耦合系数
For all couplings: Optimize coupling to give the right K-inverter value at
the center frequency
10 0
-10 -20 -30 -40 -50 -60 -70 -80 -90 15.24 15.26 15.28 15.3 15.32 15.34 15.36 15.38 15.4 15.42
frequency (GHz)
仿真与测试结果比较
data centered on f0
0
-10
-20
S (dB)
2
Kn,n1
Kn,n1 Z0B
ห้องสมุดไป่ตู้
wB
2 gn gn1
wi
gi 0 0
2
f f0
gi0
0
1 0 c 2
0
c f0
1
gi gi1
Example:
K´01=0.0775 K´12=0.0048 K´23=0.0034 K´34=0.0032
K变换器的S参数
在滤波器中心工作频率
Z0A
K01 Z0
offset
do1 = 3.845mm do2 = 3.135 mm do3 = 2.960 mm do4 = 2.972 mm do5 = 2.960 mm do6 = 3.135 mm do7 = 3.845 mm
优化谐振腔长度
For all resonators: calculate resonator length, fine tune until the structure resonates at the center frequency
带K变换器滤波器模型
1b) Calculate K-inverters (band-pass prototype parameters)
Z0A
K01 Z0
K12
Z0
K23 Z0
Z0 Kn,n+1
Z0B
g/2
g/2
K01
K01 Z0 A
w A
2 g0 g1
Ki,i1
K i ,i 1
wi
Z0i Z0,i1
BJ-140波导技术参数: a=15.8mm; b=7.9mm; 工作频率范围: 11.9~18GHz
滤波器原型
1a) Obtain low-pass prototype parameters (gi) from filter specifications (see e.g. Matthaei*)
K 1 S11
1 S11
Z0A
K01
d
Z0 g/2
K12
Z0
K 1
g/2 S21
K23
1Z02
S21
1
Z0
do
Coupling S21 (dB)
1
-16.14
2
-40.40
3
-43.47
4
-43.93
5
-43.47
6
-40.40
7
-16.14
diameter
d1 = 2.50 mm d2 = 3.50 mm d3 = 3.50 mm d4 = 3.50 mm d5 = 3.50 mm d6 = 3.50 mm d7 = 2.50 mm
15.33
l1 = 10.839 mm
l = 11.346 mm 15.34 15.35 15.36 15.37 15.38 15.39 15.4
frequency (GHz)
2
l3 = 11.395 mm
l rg 2
l4 = 11.395 mm l5 = 11.346 mm l6 = 10.839 mm
networks, and coupling structures”, Artech House, Norwood, MA, 1992
6th order
Chebychev filter
prototype
elements
g0 = 1.0000 g1 = 0.8836 g2 = 1.3966 g3 = 1.7894 g4 = 1.5528 g5 = 1.6095 g6 = 0.7667 g7 = 1.1524
g2
g4
f0 BW IL RL
gn
g0
g1
g3
gn-1
gn+1
Z0A
K01 Z0
K12
Z0
K23 Z0
Example:
f0 = 15.35 GHz BW= 32 MHz S11 < -20 dB S21 < -40 dB @ f0 ± 40 MHz
Z0 Kn,n+1
Z0B
g/2
g/2
*Matthaei, Young and Jones “Microwave filters, impedance-matching
Z0A
K01 Z0
lr
g/2
K12
Z0 g/2
S (dB)
-10
K Z -15
23
0
Z0 Kn,n+1
-20
Denne figuren er IKKE for første resonator
-25
-30
Z0B
1 r 2
r
1 2
1
2
-35
resonator length
-40 15.31
15.32