EDA365欢迎您登录!
您需要 登录 才可以下载或查看,没有帐号?注册
x
/ X" X3 u X- R
传输线 巴伦, S+ i* A8 L: L! C7 h
- V; x4 Z4 X2 |+ }' h
* Y6 t& H% F6 [& l( B0 M: Y
1.基本原型:* }5 E, B% p. B5 ^# { V9 e
, z3 v) Z& f$ s% L% M
5 V3 [& s, o0 h: ]) x2.最佳传输条件:) P* ]# q f7 `# F( j1 b. Y: y
7 _3 y+ U: E' H: w. u
: O) T m' { V, N$ ^: A! \2.2 传输线长度l应尽可能地小,工程设计中一般取<λ/8
0 R* L8 V. O# _$ A u
]1 r& a: W1 c- f' m% v* g8 X3.相关公式2 l% {5 K9 K+ s, ^
3.1传输损耗公式:2 d+ e' H# s. j& S( k! ^' X( r, @" A
8 [7 ~8 G7 \1 L+ j2 {; w. s
7 R' h- f4 J1 P# ?0 o8 d% `) T4 _ 5 K+ k* t4 ^' D' U' i6 P* x& x
3.2反射损耗公式为: 1 o1 N& ~1 T$ K0 J# h
' B2 i. ?7 _8 Y* e
; b, I$ D6 `% ]式中。Rg为源阻抗。L0为空芯绕组电感,μ’为磁导率实部, μ”为磁导率虚部。磁损耗角正切tanδm=μ”/μ’。选择μ’高、tanδm大的材料能够 同时满足传输损耗、反射损耗的指标要求。 ! \4 W4 `; Z! _; R
4 L: L) V3 t3 _3.3磁导率. _. f+ \- [, d: n3 J! A) I
铁氧体磁芯磁导率随频率变化的影响:
" V& Z" x- L! v" E磁导率随频率 变化的公式为 ) t$ u$ t4 |8 r ^8 ]
4 _# |9 x* C T. C# Q+ J Z3 _: S( E
3 L7 G9 Z5 \9 R& {7 L4 e C1 q
; K+ y5 J4 d6 e* l: o式中,S为斯诺克常数,,fr为截止频率。
& J+ S& T: ~' U' ]+ Y
5 ]. Z1 r) Z( R7 B2 m- y' E5 l将上式代人传输损耗公式进行分析得知应选择截止频率低、斯诺克常数高的磁芯材料。
5 o2 D. Q2 V& n5 B9 k, | ! b2 o0 W) y; [8 N: f2 j
综上所述,可以得出磁芯材料的选取原则是要求低频初始磁导率μ’高、截止频率fr低、斯诺克常数S 高、损耗大tanδm的材料。 7 b& b1 [7 p3 n, Z
! b1 p. ~' |& Y9 K. |0 _7 f * x7 o, l. G U6 R* {
' `& c4 N9 O' j0 o, m
4.ADS 中低端巴伦模型$ A9 E2 r, g A8 a- z! C
; v& Z7 [8 c! b- n& I6 e5 l: PBALUN1 (Balanced-to-Unbalanced Transformer (Ferrite Core))
& O$ x& M. M3 c0 b$ }. i: D3 iSymbol 9 o1 ]* d1 k0 y6 X+ h
) z& w' [0 n. @. ~
Range of Usage
* k2 r' T% I" d8 x( B! p/ R( {Z > 0, Len > 0, AL > 0
! h r: r( o- Q, I) A9 RK ≥ 1: y+ x. J, u3 {3 C. s
A ≥ 0: _- ]3 E- q% B5 P
F ≥ 0
: i" E- Z. C' |' `2 v) y5 zN ≥ 1 2 ?- Q! p$ N) H% a+ t; ]9 D& A; e
Parameters ) ?$ m5 a* s1 S6 D7 k) n
| Name | Description | Units | Default | | Z | Characteristic impedance of transmission line | Ohm | 50.0 | | Len | Physical length of transmission line | mil | 12.0 | | K | Effective dielectric constant(有效介电常数) | None | 2.0 | | A | Attenuation (per unit length) of transmission line | dB/meter | 0.0 | | F | Frequency for scaling attenuation | GHz | 1.0 | | N | Number of turns | None | 5.0 | | AL | Inductance index(电感指数) | nH | 960.0 | | TanD | Dielectric loss tangent (介质损耗角正切) | None | 0 | | Mur | Relative permeability (相对磁导率) | None | 1 | | TanM | Magnetic loss tangent(磁损耗正切) | None | 0 | | Sigma | Dielectric conductivity (介电导电率) | None | 0 | | Temp | Physical temperature | °C | None |
5 G7 o( u* @/ b$ S* B· This component is a length of transmission line(specified by Z, Len, K, A and F) coiled around a ferrite core.
0 I: ^2 i7 F! }6 x/ AChoking inductance Lc accountsfor low-frequency roll-off and is given by
. }% T$ i# c1 ]1 p/ ULc = N2 × AL
8 S3 Y9 T3 R. R3 d7 M. b0 L- r7 tA(f) = A (for F = 0)" O6 \$ c! L9 N
A(f) = A(F) × file:///C:/Users/wanghai/AppData/Local/Temp/msohtmlclip1/01/clip_image013.png
" Q4 z* q$ z- D2 l+ i3 c& t7 _(for F ≠ 0)
/ V X0 U5 r a8 ?& m+ l: j2 ^# x7 ~where* Q+ E: S1 c$ P& b3 f2 T
f = simulation frequency# p. n' R" `: t/ f
F = reference frequency for attenuation / U. R( a, \+ G, @5 N6 a5 S, j2 X% c
For time-domain analysis, an impulseresponse obtained from the frequency-domain analytical model is used. Thiscomponent has no default artwork associated with it.
" g, E: _9 b/ g· The "Temp" parameter is only used in noisecalculations. - X+ u1 h; M" U7 L# O% W; a( R
· For noise to be generated, the transmission line must belossy (loss generates thermal noise). # |1 _ i i/ G8 J! F& k1 J$ `
; r5 @" D" O, d+ v, k
+ c" z0 C: m9 z( Q5.小节:
$ w; H0 `) I k4 l" H6 m$ S# v调节ADS 中的参数可以仿真出巴伦对应的传输损耗;
/ t$ ^6 y5 y, K7 ?介电常数环节需要进一步讨论;. 2 y: P g L& Y( L$ Q
/ A3 E9 e, Z; Q* [ C' ]/ N# z$ ^
% R2 \- j& `) k0 G
|