CN105896011A - Design and calculation method for inner conductor of quasi-microstrip ferrite circulator - Google Patents

Abstract

The invention relates to a design and calculation method for an inner conductor of a quasi-microstrip ferrite circulator. The design and calculation method for the inner conductor of the quasi-microstrip ferrite circulator belongs to the technical field of communication electronic component and assembly design. According to the invention, a thin copper strip is utilized to replace a microstrip conductor evaporated at the surface of a ferrite so as to form a quasi-microstrip inner conductor. A triangular part of the inner conductor forms a shunt inductor L0 and a capacitor C0, three leading-out ports are mutually of 120-degree rotational symmetry, each narrow-band line forms an inductor LP, and each broad-band line forms a capacitor CP. The upper surface and the lower surface of the inner conductor are closely contacted with an upper aluminum cavity and a lower aluminum cavity respectively through the ferrite, and the upper aluminum cavity and the lower aluminum cavity are connected by four screws so as to form a shunt metal-ferrite-metal interlayer capacitor. The design and calculation method solves a key technological problem that the shunt inductor L0, the capacitor C0, the inductors LP and the capacitors CP are difficult to be accurately calculated by mathematics for a long time; and a formula for calculating the diameter D of the area of the capacitors (C0+3CP) formed by the inner conductor, the area AP of the capacitor CP formed by the broad-band line and the length lP of the inductor LP formed by the narrow-band line is derived. A calculation result relatively conforms to the reality, the blindness in new product trial-manufacture is reduced, and the method has a push and promotion effect for industrial technology development.

Description

A kind of design and calculation method of quasi-micro-strip ferrite circulator inner wire

(1) technical field

The invention belongs to Communication Electronic Element and assembly design field.

(2) background technology

Knowable to microwave engineering principle and ferrite physics, gyromagnetic ferrite is that a kind of existing gyromagnetism has again The ferrimagnetism material of dielectricity, in bias field H₀Lower produced tensor magnetic conductance is jointly acted on radiofrequency signal Rate is the theoretical basis of ferrite circulator work.Ferrite circulator has three ports, due to tensor magnetic conductance The existence of rate, ferrite circulator is provided with nonreciprocity, if signal is transmission side from port 1 → 2 → 3 To, then isolation direction is just become from port 3 → 2 → 1；Utilizing this characteristic, ferrite circulator exists Communication system can be made duplexer, it is achieved launch signal and receive the automatic conversion of signal.If ferrite core One port (such as 3 port) of row device connects the resistance identical with port Impedance, has just become two-port ferrum Oxysome isolator, if signal is transmission direction from port 1 → 2, then from port 2 → 1 side of isolation exactly To；Ferrite isolator plays isolation, matching effect at signal source outfan and Amplifier stage.

The science skill that the manufacturing and designing of ferrite circulator is microwave engineering principle and magnetics rationale combines Art.In view of they weights in radar, navigation, mobile communication, radio and television and other electronic equipment Acting on, China began to study in late 1950s, experienced by by distributed constant, lump Parameter, micro-strip designing technique research manufactures the evolution of ferrite circulator, uses these designing techniques to grind The various ferrite circulators of system have all played can not underestimate in different frequency ranges and different application scenarios Effect.But due to the characteristic that they are intrinsic, in terms of combination property, weak point all it is individually present, such as, Big by the ferrite circulator volume of distributed constant design；By the ferrite circulator structure of lumped parameter design Complexity, insertion loss is big, and temperature performance is poor；And the micro belt conductor of micro-strip ferrite circulator is to pass through photoetching Directly be deposited with on ferrite surfaces with vacuum coating, manufacturing process relates to ferrite grind, polishing, The complicated technique such as photoetching, vacuum coating, and design, debug difficulty, stability and input, output The soldering resistance of port is the poorest.Make us the most regrettably, for a long time, in above-mentioned various designing techniques, pure Theoretical and conceptualization method for designing is in the majority, lacks complete design program, and clear and definite computational methods are with accurate Result of calculation, to such an extent as to new product manufacture experimently in often with the biggest blindness, much time wealth.

(3) summary of the invention

The invention aims to solve the most traditional designing technique and be difficult to accurately calculate with mathematics ferrum The crucial technical problem of each parameter that oxysome circulator inner wire is constituted, it is provided that quasi-micro-strip ferrite circulator Inner wire design-calculated complete design program, clear and definite computational methods and accurately result of calculation.

Solution problem the technical scheme is that and specify that ferritic Effective permeability μ the most theoretically_e It is to affect the inductance that quasi-micro-strip ferrite circulator inner wire is constituted, ferritic DIELECTRIC CONSTANT ε_rIt it is quasi-micro-strip Ferrite circulator inner wire constitutes the figure of merit of electric capacity；Ferritic thickness h is to affect inner wire to constitute Inductance and the important parameter of electric capacity, they to design calculate quasi-micro-strip ferrite circulator inner wire constitute Inductance and electric capacity have highly important effect.

The present invention solves the practical solutions of problem: replace evaporation on ferrite surfaces with thin copper belt Micro belt conductor, constitutes quasi-micro-strip inner wire.Inner wire part triangular in shape constitutes shunt inductance L₀With electric capacity C₀, Three draw port each other 120 ° rotationally symmetrical, narrowband line constitute inductance L_P, broadband line constitutes electric capacity C_P。 Fig. 2 is the equivalent circuit of inner wire.Inner wire above and below is in close contact with aluminum cavity respectively through ferrite, Connect upper and lower aluminum cavity with 4 screws, constitute metal ferrites metal sandwich electric capacity in parallel. Creative the most traditional designing technique that solves is difficult to accurately calculate inner wire composition with mathematics also Connection inductance L₀With electric capacity C₀, the inductance L of narrowband line composition_PThe electric capacity C constituted with broadband line_PKey skill Art problem；It is deduced in calculating by the method calculating metal ferrites metal sandwich electric capacity in parallel Conductor constitutes electric capacity (C₀+3C_P) the diameter D of area, broadband line constitutes electric capacity C_PArea A_PPublic affairs Formula；By the method seeking microstrip line unit length inductance, it is deduced calculating narrowband line and constitutes inductance L_PLength l_PFormula.Result of calculation quite meets with reality, saves the design time, it is simple to physics realization, reduces new product Blindness in trial-production.The quasi-micro-strip ferrite circulator that the designing technique provided by the present invention makes is comprehensive Can be excellent, insertion loss is little, bandwidth, and temperature stability is good, can bear high-power, assembles, the side of debugging Just, structure can be designed to the smallest and the most exquisite, compact, and can be used for microwave hybrid integrated circuit；To industrial technology Progressive, it is achieved ferrite circulator miniaturization, miniaturization has promotion, facilitation.

(4) detailed description of the invention

1, the shunt inductance L that inner wire part triangular in shape is constituted₀With electric capacity C₀Calculating: ignoring electromagnetism It is lost ideally, L₀C₀It is a low impedance circuit during parallel circuit resonance, its characteristic impedance valueAccording to document " Jiang Renpei, Xu Jidong " Thin Type Strip Line Circulator with internal matching LC-networks”10th international Conference on microwave Ferrites PP344-348september 1990 " report, its resistance value is between 10～20 ohm.Work as angular frequency $\mathrm{\ω}=\frac{1}{\sqrt{L_0{C}_0}}$ Time, draw:

$\begin{array}{cc}{C}_0=\frac{1}{\mathrm{\ω}{Z}_0}& \mathrm{PF}\end{array}$ (picofarad)

$L_0={Z_0}^2{C}_0$ (or $L_0=\frac{Z_0}{\mathrm{\ω}}$ ) nH (nanohenry)

In formula, ω=2 π f, f are as the criterion the operating frequency of micro-strip ferrite circulator, and unit is Hz.

2, the inductance L that narrowband line is constituted_P, the electric capacity C of broadband line composition_PCalculating: as it is shown on figure 3, L_P And C_PCan be considered the element of the low-pass filtering impedance transformer of component number n=2, portion triangular in shape for inner wire Divide the shunt inductance L constituted₀With electric capacity C₀The characteristic impedance Z formed₀As source impedance, if terminal impedance is Z_L, its impedance transformation ratioOperational frequency bandwidth when quasi-micro-strip ferrite circulator(ω_H、f_HFor maximum operating frequency；ω_L、f_LFor lowest operating frequency；ω₀、 f₀Centered by operating frequency) determine after, from table 1, check in normalization component valueRenormalization is asked Go out:

$\begin{array}{cc}\mathrm{Lp}=\frac{g_1{Z}_0}{\mathrm{\ω}}& \mathrm{nH}\end{array}$

$\begin{array}{cc}\mathrm{Cp}=\frac{g_2}{\mathrm{\ω}{Z}_0}& \mathrm{PF}\end{array}$

Component value g during table 1n=2₁Relation with Δ F and R

3, inner wire constitutes electric capacity (C₀+3C_P) the calculating of diameter D of area:

When inner wire constitutes electric capacity (C₀+3C_P) area beTime, push away from the formula calculating interlayer electric capacity Derive the electric capacity (C that inner wire is constituted₀+3C_P) the formula of diameter D of area be:

$\begin{array}{cc}D=3.793\sqrt{\frac{(C_0+3\mathrm{Cp})h}{{\mathrm{\ϵ}}_r}}& \mathrm{cm}\end{array}$

In formula, h is ferritic thickness, and unit is centimetre；ε_rFor ferritic dielectric constant.

This parameter is to choose the important evidence of ferrite diameter, in order to C₀、C_PAnd L_PBetween reserve interval, The ferrite diameter chosen ratio calculates big 1～2 millimeter of the D value obtained.

4, the electric capacity C that inner wire broadband line is constituted_PArea A_PCalculating: because C_PIt is by inner wire broadband The electric capacity parallel connection that line upper and lower faces is constituted respectively through ferrite obtains, thus public by calculating interlayer electric capacity Electric capacity when formula is derived should be one side electric capacitySo, the electric capacity C that calculating broadband line is constituted is derived_P Area A_PFormula be:

$\begin{array}{cc}\mathrm{Ap}=5.65\frac{\mathrm{Cph}}{{\mathrm{\ϵ}}_r}& {\mathrm{cm}}^2\end{array}$

In formula, h is ferritic thickness, and unit is centimetre；ε_rFor ferrite dielectric constant.

5, the inductance L that inner wire narrowband line is constituted_PLength l_PCalculating: utilize seek microstrip line unit length The method of inductance, derives and calculates the inductance L that narrowband line is constituted_PLength l_PFormula be:

$\begin{array}{cc}\mathrm{lp}=\frac{\mathrm{\μeLp}}{2\ln (\frac{8h}{W}+\frac{W}{4H})}& \mathrm{cm}\end{array}$

In formula, ln is natural logrithm, and w is the width of inner wire narrowband line, and h is ferritic thickness, and unit is equal For centimetre.μ_eIt it is ferritic Effective permeability.

Because ferritic Effective permeability μ_eIt it is ferrite saturation magnetization 4πms bias field H₀And work Making the function of angular frequency, calculate more complicated, design can be with practical experience value in calculating.

6, physics realization: D, A obtained according to above-mentioned calculating_PAnd l_PValue, by computer autoCAD Design quasi-micro-strip ferrite circulator inner wire pattern.

(5) accompanying drawing explanation

Fig. 1 quasi-micro-strip ferrite circulator inner wire schematic diagram

Symbol L in figure₀Represent the shunt inductance that inner wire part triangular in shape is constituted

C₀Represent the shunt capacitance that inner wire part triangular in shape is constituted

L_PRepresent the inductance that inner wire narrowband line is constituted

C_PRepresent the electric capacity that inner wire broadband line is constituted

The inner wire equivalent circuit of the quasi-micro-strip ferrite circulator of Fig. 2

Because it is 120 rotationally symmetrical each other that inner wire three draws port, figure only depicts parallel circuit L₀C₀ The L of port is drawn with one of them_P、C_P。

Symbol L in figure₀Represent the shunt inductance that inner wire part triangular in shape is constituted

C₀Represent the shunt capacitance that inner wire part triangular in shape is constituted

L_PRepresent inner wire one and draw the inductance that port narrowband line is constituted

C_PRepresent inner wire one and draw the electric capacity that port broadband line is constituted

Fig. 3 low-pass filtering impedance transformer schematic diagram

Symbols Z in figure₀Represent the shunt inductance L that inner wire part triangular in shape is constituted₀With electric capacity C₀Formed Impedance

Z_LGC group connector impedance

L_PRepresent the inductance element that inner wire narrowband line is constituted

C_pRepresent the capacity cell that inner wire broadband line is constituted

g₁Represent L_PTo Z₀Normalization inductance

g₂Represent C_PTo Z₀Normalization electric capacity

Fig. 4 quasi-micro-strip ferrite circulator inner wire constitutes metal ferrites metal sandwich electricity in parallel Hold schematic diagram

In figure, numbering 1 represents inner wire

2 represent Double layer iron oxysome

3 represent upper and lower aluminum cavity

4 represent four screws connecting upper and lower aluminum cavity

(6) detailed description of the invention citing

Example A: when operational frequency bandwidth Δ F≤0.1 of quasi-micro-strip ferrite circulator, whole parameters are all pressed Center operating frequency ω₀Design calculates.

Example B: when operational frequency bandwidth Δ F >=0.1 of quasi-micro-strip ferrite circulator, L₀C₀Press with D Low operating frequency ω_LDesign calculates；And L_P、C_P、A_PAnd l_PBy maximum operating frequency ω_HDesign calculates.

Citing (range of application of the present invention is not limited to this): evaluation work to be designed is in the standard of 960～1200MHz The inner wire of micro-strip ferrite circulator, terminal impedance Z_L=50 Ω, its design program and computational methods are as follows:

Center operating frequency: $f_0=f0=\frac{\mathrm{fH}+\mathrm{fL}}{2}=\frac{1200+960}{2}=1080\mathrm{MHz}$

Operational frequency bandwidth: $\mathrm{\ΔF}=\frac{\mathrm{fH}-\mathrm{fL}}{f0}=\frac{1200-960}{1080}\≈0.22$

Implement by example B, choose Z₀=15 Ω, if ferrite thickness h=0.18 centimetre, DIELECTRIC CONSTANT ε_r=14, So:

$C_0=\frac{1}{{\mathrm{\ω}}_L{Z}_0}=\frac{1}{6.28\×960\×{10}^6\×15}=11.06\mathrm{pF}$

L₀=Z₀ ²C=15²×11.06×10^-12=2.49nH

According to Δ F=0.22, impedance transformation ratioG is checked in from table 1₁=1.407, $g_2=\frac{g1}{R}=\frac{1.407}{3.33}=0.4225$

$\begin{array}{cc}\mathrm{Lp}=\frac{g_1{Z}_0}{{\mathrm{\ω}}_H}=\frac{1.407\×15}{6.28\×1200\×{10}^6}\≈2.80& \mathrm{nH}\end{array}$

$\begin{array}{cc}\mathrm{Cp}=\frac{g_2}{{\mathrm{\ω}}_H{Z}_0}=\frac{0.4225}{6.28\×1200\×{10}^6\×15}\≈3.74& \mathrm{pF}\end{array}$

$D=3.793\sqrt{\frac{(C0+3\mathrm{CP})h}{{\mathrm{\ϵ}}_r}}=3.793\sqrt{\frac{(11.06+3\×3.74)\×0.18}{14}}=2.031\mathrm{cm}=20.31\mathrm{mm}$

$\mathrm{Ap}=5.65\frac{\mathrm{Cph}}{{\mathrm{\ϵ}}_r}=5.65\frac{3.74\×0.18}{14}=0.2716{\mathrm{cm}}^2=27.16{\mathrm{mm}}^2$

As narrowband line width W=0.19cm, during ferrite thickness h=0.18cm, μ e=0.6,

$\mathrm{lp}=\frac{\mathrm{\μeLp}}{2\ln (\frac{8h}{W}+\frac{W}{4h})}=\frac{0.6\×2.8}{2\ln (\frac{8\×0.18}{0.19}+\frac{0.19}{4\×0.18})}\≈0.407\mathrm{cm}=4.07\mathrm{mm}$

According to calculating D, the A obtained_PAnd l_PJust can easily design the interior of quasi-micro-strip ferrite circulator Conductive pattern.

Table 2 is the comparison of calculated value and actual applicable value.

Claims (8)

1. The design and calculation method of the most quasi-micro-strip ferrite circulator inner wire, is characterized in that: replace evaporation with thin copper belt Micro belt conductor on ferrite surfaces, constitutes quasi-micro-strip inner wire；Inner wire part triangular in shape is constituted also Connection inductance L₀With electric capacity C₀, three draw port each other 120 ° rotationally symmetrical, narrowband line constitute inductance L_P, Broadband line constitutes electric capacity C_P；The above and below of inner wire closely connects with upper and lower aluminum cavity respectively through ferrite Touch, connect upper and lower aluminum cavity with 4 screws and constitute metal ferrites metal sandwich electric capacity in parallel.
2. The most according to claim 1, inner wire part triangular in shape constitutes shunt inductance L₀With electric capacity C₀, arrowband Line constitutes inductance L_P, broadband line constitutes electric capacity C_P, it is characterized in that: creatively solve and accurately count with mathematics Calculate L₀、C₀、L_P、C_PCrucial technical problem, their value can be obtained respectively by following equation:

   $C_0=\frac{1}{\mathrm{\ω}{Z}_0}\mathrm{PF}$

   $\mathrm{Lp}=\frac{g_1{Z}_0}{\mathrm{\ω}}\mathrm{nH}$ $\mathrm{Cp}=\frac{g_2}{\mathrm{\ω}{Z}_0}\mathrm{PF}$
3. The most according to claim 1, inner wire above and below closely connects with upper and lower aluminum cavity respectively through ferrite Touch, connect upper and lower aluminum cavity with 4 screws, constitute metal ferrites metal sandwich electricity in parallel Hold, it is characterized in that: be deduced calculating inner wire and constitute electric capacity (C₀+3C_P) the diameter D of area, structure Become electric capacity C_PArea A_PWith composition inductance L_PLength l_PFormula, parameter D, A_PAnd l_PValue can press Following equation is obtained:

   $D=3.793\sqrt{\frac{(C_0+3\mathrm{Cp})h}{{\mathrm{\ϵ}}_r}}\mathrm{cm}$

   $\mathrm{Ap}=5.65\frac{\mathrm{Cph}}{{\mathrm{\ϵ}}_r}{\mathrm{cm}}^2$

   $\mathrm{lp}=\frac{\mathrm{\μeLp}}{2\ln (\frac{8h}{W}+\frac{W}{4h})}\mathrm{cm}.$
4. 4., according to ferrite described in claim 1 and 3, it is characterized in that: existing gyromagnetism has again dielectricity, it Effective permeability μ_eIt is to affect the inductance that inner wire is constituted, DIELECTRIC CONSTANT ε_rIt it is the high-quality of inner wire composition electric capacity Parameter, its thickness h is to affect the important parameter of inductance and electric capacity.
5. 5. constitute shunt inductance L according to inner wire part triangular in shape described in claim 1 and 2₀With electric capacity C₀, It is characterized in that: inner wire constitutes shunt inductance L₀With electric capacity C₀The shape of area include triangle, circular arc three Dihedral, trilobal, hexagon and circular.
6. 6. constitute electric capacity C according to inner wire broadband line described in claim 1 and 2_P, it is characterized in that: inner wire broadband Line constitutes electric capacity C_PThe shape of area include rectangle, circular and arch.
7. Replace evaporation micro belt conductor on ferrite surfaces with thin copper belt the most according to claim 1, constitute standard Micro-strip inner wire, is characterized in that: the thickness of thin copper belt is 0.2～1.2mm.
8. The most quasi-micro-strip ferrite circulator, is characterized in that: quasi-micro-strip ferrite circulator Three ports, one port of any of which are had to connect the resistance identical with port Impedance, just become two-port Quasi-microstrip ferrite isolator.