CN203747008U - Small-sized hybrid ring with filtering function - Google Patents

Abstract

The utility model discloses a small-sized hybrid ring with a filtering function, which comprises an upper-layer microstrip structure, a middle dielectric substrate and a bottom-layer metal floor, wherein the upper-layer microstrip structure comprises a first port, a second port, a third port, a fourth port, a first filtering K converter, a second filtering K converter, a third filtering K converter and a filtering -K converter; the first filtering K converter is connected between the first port and the second port; the second filtering K converter is connected between the first port and the third port; the third filtering K converter is connected between the third port and the fourth port; and the filtering -K converter is connected between the second port and the fourth port. The small-sized hybrid ring with a filtering function has the advantages of small size, good harmonic suppression performance, broad stopband characteristics and good isolation degree.

Description

A kind of miniaturization hybrid ring with filter function

Technical field

The utility model relates to technical field of micro communication, particularly a kind of miniaturization hybrid ring with filter function.

Background technology

Along with the fast development of radio communication, the complexity of wireless device and portable requirement is constantly promoted, this miniaturization to Wireless Telecom Equipment has proposed requirements at the higher level.RF/Microwave front-end circuit is the important component part of wireless system equipment and terminal, except comprising that active device (as amplifier, frequency mixer etc.), the passive devices such as hybrid ring are also its significant components.The miniaturization technology of active device is very ripe, and passive device still faces a key technology difficult problem for miniaturization.

Hybrid ring is widely used in modern microwave Circuits System, such as frequency mixer, power amplifier and antenna feed structure etc.Traditional hybrid ring is made up of 3 sections of quarter-wave transmission lines and 1 section of four/three-wavelength transmission line, and volume is large and have a high order harmonic component.

For miniaturization issues, the method for designing that Chinese scholars adopts mainly contains: 1) replace quarter-wave transmission line or four/three-wavelength transmission line with the element of compact conformation; 2) other miniaturization methods, for example, adopt T equivalent-circuit model after microwave C element, fold line, defect ground structure, Stepped Impedance structure, T-shaped equivalent structure, coupling line, improvement etc.

Suppress for harmonic wave, mainly adopt following methods: the 1) introducing of defect ground structure and Stepped Impedance, has not only realized the miniaturization of hybrid ring, and has suppressed harmonic wave; 2) parallel lines coupled structure, suppresses to realize miniaturization and harmonic wave; 3) with two groups of accurate winding inductor and interdigital capacitors concentrated in parallel, produce two transmission zeros, thereby suppress high order harmonic component: 4) adopt high-impedance transmission line and interdigital capacitor to suppress second harmonic.

In radio-frequency (RF) front-end circuit, hybrid ring and band pass filter often coexist in a system, and conventional design method is to be all that independent design rear class combines as a whole two devices, and integrated circuit volume does not significantly reduce.For further reducing integrated circuit volume, Chinese scholars has proposed following design: 1) with four TE01 mould dielectric resonators come integrated the two; 2) hybrid ring of the high stopband isolation based on microstrip network shape filter; 3) 180 of the compact conformation based on quarter-wave and half-wavelength micro-strip resonantor degree filtering electric bridges; 4) based on a bilateral band hybrid ring for nodel line loading Stepped Impedance resonator; 5) the logical hybrid ring of the miniaturization band based on LTCC.

Utility model content

The purpose of this utility model is to adopt four filtering ± K converters with band-pass response characteristic to replace quarter-wave transmission line or the four/three-wavelength transmission line in conventional hybrid ring, and a kind of miniaturization hybrid ring with filter function is provided.

The utility model adopts following technical scheme:

A kind of miniaturization hybrid ring with filter function, comprise upper strata microstrip structure, intermediate medium substrate and underlying metal floor, described upper strata microstrip structure comprises the first port, the second port, the 3rd port, the 4th port, the first filtering K converter, the second filtering K converter, the 3rd filtering K converter and filtering-K converter, wherein the first filtering K converter is connected between the first port and the second port, the second filtering K converter is connected between the first port and the 3rd port, the 3rd filtering K converter is connected between the 3rd port and the 4th port, filtering-K converter is connected between the second port and the 4th port.

Described first, second, third filtering K transformer configuration is identical, and the short-circuited transmission line that has loaded capacitor C by 2 two ends forms, and 2 short-circuited transmission lines are folded into L-type, by capacitor C _eunsymmetric structure in series is II type coupled structure.

Described filtering-K converter is also made up of the short-circuited transmission line of 2 two ends loading capacitance C, and 2 short-circuited transmission lines be folded into U-shaped, by capacitor C _eformation symmetrical structure in parallel is I type coupled structure.

Described formation filtering K converter is identical with the parameter of the short-circuited transmission line of filtering-K converter, and length is 36.1mm, and width is 0.3mm.

The relative dielectric constant of described intermediate medium substrate is 3.38, and thickness is 0.81mm.

The beneficial effects of the utility model:

The utility model volume is little, harmonic wave rejection good, have wideband stopband characteristic and good isolation.

Brief description of the drawings

Fig. 1 is the theory diagram of the miniaturization hybrid ring of a kind of integrated filter function of the utility model;

Fig. 2 (a) is the equivalent electric circuit of the utility model filtering-K converter (I type coupled structure), and Fig. 2 (b) is the equivalent electric circuit of the utility model filtering K converter (II type coupled structure).

Fig. 3 is the simulation result of the utility model I type coupled structure;

Fig. 4 is the simulation result of the utility model II type coupled structure;

Fig. 5 (a) is the channel structure of the first port to the four ports;

Equivalent electric circuit when Fig. 5 (b) is the utility model the first port excitation;

Equivalent electric circuit when Fig. 6 is the utility model the 4th port excitation;

Fig. 7 is a kind of miniaturization hybrid ring circuit structure diagram with filter function of the utility model;

Fig. 8 is when in the utility model embodiment 1, the first port encourages, the emulation of the first port and the 4th interport isolation and measured value comparison diagram;

When Fig. 9 (a) is the first port excitation, S when push-push operation ₁₁, S ₂₁and S ₃₁emulation and measured result comparison diagram;

When Fig. 9 (b) is the first port excitation, S in passband when push-push operation ₂₁and S ₃₁emulation and measured result Detail contrast figure;

When Fig. 9 (c) is the first port excitation, ∠ S when push-push operation ₂₁-∠ S ₃₁emulation and measured result comparison diagram;

When Figure 10 (a) and (b), (c) are the first port excitation, emulation when reverse operation and measured result comparison diagram, when wherein Figure 10 (a) is the first port excitation, S when anti-phase work ₁₁, S ₂₁and S ₃₁emulation and measured result comparison diagram; When Figure 10 (b) is the first port excitation, ∠ S when anti-phase work ₂₁-∠ S ₃emulation and measured result Detail contrast figure; When Figure 10 (c) is the first port excitation, S when anti-phase work ₂₂, S ₃₃and S ₄₁emulation and measured result comparison diagram.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but execution mode of the present utility model is not limited to this.

Embodiment

As shown in Figure 1, a kind of miniaturization hybrid ring with filter function, comprises upper strata microstrip structure, intermediate medium substrate and underlying metal floor, and described upper strata microstrip structure comprises the first port P ₁, the second port P ₂, the 3rd port P ₃, the 4th port P ₄, the first filtering K converter, the second filtering K converter, the 3rd filtering K converter and filtering-K converter, first, second, third filtering K converter is used for replacing quarter-wave transmission line,-K filtering transformation device is used for replacing four/three-wavelength transmission line, and concrete structure is: the first filtering K converter is connected to the first port P ₁and the second port P ₂between, the second filtering K converter is connected to the first port P ₁and the 3rd port P ₃between, the 3rd filtering K converter is connected between the 3rd port and the 4th port, and filtering-K converter is connected to the second port P ₂and the 4th port P ₄between.

As shown in Figure 6, described first, second, third filtering K transformer configuration is identical, and the short-circuited transmission line that has loaded capacitor C by 2 two ends forms, and 2 short-circuited transmission lines are folded into L-type, by capacitor C _eunsymmetric structure in series, the equivalent electric circuit II type coupled structure of described filtering K converter is as shown in Fig. 2 (b), and coupled structure calculation of parameter is as follows: θ ₁=27.5 °, θ ₂=5.2 °, C=8.2pF, C _e=1.2pF.Operating frequency is at 470MHz, and second harmonic is at 2.8GHz (6f ₀).

Described filtering-K converter is made up of the short-circuited transmission line of 2 two ends loading capacitance C, and 2 short-circuited transmission lines be folded into U-shaped, by capacitor C _eformation symmetrical structure in parallel, as shown in Figure 2 (a) shows, as shown in Figure 3, coupled structure parameter is θ to the simulation result of I type coupled structure to its equivalent electric circuit I type coupled structure ₁=27.5 °, θ ₂=5.2 °, C=8.2pF, C _e=1.2pF.Visible, operating frequency f ₀at 470MHz, second harmonic is at 2.8GHz(6f ₀).

Identical with Fig. 4 bandwidth from Fig. 3, the Q of two kinds of coupled structures _eidentical with coupling length, can make like this hybrid ring there is filter function.

Therefore two kinds of can be equivalent to ± K of coupled structure converters, therefore can replace by coupled structure, quarter-wave in conventional hybrid ring is propped up nodel line and four/three-wavelength props up nodel line, the utility model can push-push operation, also can reverse 180 degree work, and detailed process is as follows:

(1) push-push operation

When push-push operation, all input powers from the first port should be distributed to the second port and the 3rd port by homophase, do not have power from first end oral reflex out, also do not have electric current to flow into the 4th port.

Circuit analysis is as follows: first, whole circuit should consider that all input powers are all assigned to the second port and the 3rd port.Secondly, analyze and how to go to realize constant power coefficient and same phase shift.

According to match circuit, in the time that the first port is energized, this port should mate.In addition, the 4th port cannot emergent power loss.Necessary condition can be expressed as follows:

$\left\{\begin{array}{cc}{S}_{11}=0& \left(1a\right)\\ S_{41}=0& \left(1b\right)\end{array}\right.$

In the time that the first port is energized, there is Liang Tiao road from the first port to the four ports, the transmission matrix of low side channel PathI and top-channel PathII can be written as:

$\begin{array}{c}\left[\begin{array}{cc}{A}_I& B_I\\ C_I& D_I\end{array}\right]=\left[\begin{array}{cc}0& {\mathrm{jK}}_1\\ \frac{-1}{{\mathrm{jK}}_1}& 0\end{array}\right]\left[\begin{array}{cc}1& 0\\ \frac{1}{Z_0}& 1\end{array}\right]\left[\begin{array}{cc}0& {\mathrm{jK}}_1\\ \frac{-1}{{\mathrm{jK}}_1}& 0\end{array}\right]\\ =\left[\begin{array}{cc}-1& \frac{{{-K}^2}_1}{Z_0}\\ 0& -1\end{array}\right]\end{array}---\left(2\right)$

$\begin{array}{c}\left[\begin{array}{cc}{A}_I& B_I\\ C_I& D_I\end{array}\right]=\left[\begin{array}{cc}0& {\mathrm{jK}}_1\\ \frac{-1}{{\mathrm{jK}}_1}& 0\end{array}\right]\left[\begin{array}{cc}1& 0\\ \frac{1}{Z_0}& 1\end{array}\right]\left[\begin{array}{cc}0& {\mathrm{jK}}_2\\ \frac{-1}{{\mathrm{jK}}_2}& 0\end{array}\right]\\ =\left[\begin{array}{cc}\frac{K_1}{K_2}& \frac{K_1{K}_2}{Z_0}\\ 0& K_1\end{array}\right]\end{array}---\left(3\right)$

Based on formula (3), S parameter can be obtained by abcd matrix:

$S_{41}=\frac{-2Y_{41}{Y}_0}{(Y_{11}+Y_0)(Y_{44}+Y_0)-Y_{41}{Y}_{14}}---\left(4\right)$

If Y ₄₁=0, S so ₄₁=0, therefore do not have power to flow out from the 4th port.According to transmission matrix and impedance matrix, admittance parameter Y ₄₁can be expressed as follows:

$Y_{41}=-\frac{1}{B_I}-\frac{1}{B_{\mathrm{II}}}=\frac{{K^2}_1}{Z_0}-\frac{K_1{K}_2}{Z_0}---\left(5\right)$

Work as Y ₄₁=0, can obtain:

K ₁=K ₂ (6)

Therefore, when the condition of formula (6) meets, S ₄₁=0, can realize the isolation of the 4th port.Because two kinds of coupled structures have band-pass response, at passband, two kinds of possess again ± K of coupled structure inverter functionality, the first port and the 4th port can well be isolated so.

According to the outer response of band, the signal coming from the first port can not be sent to the 4th port, because signal is suppressed at stopband by two kinds of coupled structures.Therefore, the first port and the 4th port are isolated by wide stopband.

In the time that the first port and the 4th port are isolated, the 4th port does not have electric current to flow through, and port voltage U4 is 0 so, that is:

U ₄=0 (7)

Like this, the short circuit of a point in Fig. 5 (a), circuit reduction is Fig. 5 (b), wherein K ₁represent a kind of form of filtering+k converter ,-K ₂represent a kind of form of filtering-K converter, but, due to the characteristic of filtering ± K converter, short dot after filtering ± become open circuit after K converter.

At frequency domain, power is distributed to the second port and the 3rd port with identical phase shift.In order to realize the coupling of the first port, input impedance Z _in2and Z _in3meet formula (8):

Z _in2/Z _in3=Z ₀ (28)

On the other hand,

$Z_{\mathrm{in}2}=Z_{\mathrm{in}3}=\frac{{K_1}^2}{Z_0}---\left(9\right)$

Can be obtained by formula (6) (8) (9):

$K_1=K_2=\sqrt{2}{Z}_0---\left(10\right)$

According to formula, be easy to obtain K ₁and K ₂.

Know according to analysis, use coupled structure I and II, the power of the first port can by same phase shift be distributed to the second port and the 3rd port, and the 4th port is isolated and (works as K ₁=K ₂.).

In addition, coupled structure can also realize filtering characteristic.Know based on above analysis, in the time that the first port is energized, by the type coupled structure between the first port and the second port, between the first port and the 3rd port, be distributed to the second port and the 3rd port from the power of the first port input.

The S parameter ratio S of the second port and the 3rd port ₂₁/ S ₃₁determined by these two I type coupled structures.Therefore, S ₂₁/ S ₃₁filter response and coupled structure the same.In addition,, owing to being etc. that merit is divided, insertion loss is better than 3dB.

2) reverse operation state

When reverse operation, all power from the 4th port input should be distributed to the second port and the 3rd port (phase difference 180 is spent), and the first port is isolated.Analysis during according to push-push operation is above known, in the time that the 4th port is energized, works as K ₁=K ₂time, the first port and the 4th port are isolated, and now the first port does not have power stage, and the b point in Fig. 5 (b) is short-circuit ground.Like this, whole circuit can be reduced to shown in Fig. 6.When $K_1=K_2=\sqrt{2}{Z}_0$ Time,

Z _in4=Z _in5=2Z ₀ (11)

Like this, the 4th port can obtain good coupling, and power can be distributed to the second port and the 3rd port.In addition, when the signal that the 4th port is come in, Jing Guo – K filtering transformation device or+K filtering transformation device is while delivering to the second port and the 3rd port, two-port signal phase out differs 180 degree.

In addition, in the time that the 4th port is energized, equivalent electric circuit can be reduced to shown in Fig. 6, in Fig. 6, and K ₁represent a kind of form of filtering+k converter ,-K ₂represent a kind of form of filtering-K converter, the power that the 4th port comes is assigned to the second port and the 3rd port through the I type coupled structure between the first port and the second port, the first port and the 3rd port or II type coupled structure.S ₂₄and S ₃₄response determined by I type coupled structure and II type coupled structure respectively, therefore, S ₂₁and S ₃₁also identical with I type coupled structure and II type coupled structure respectively of frequency response.In addition,, owing to being etc. that merit is divided, Insertion Loss is better than 3dB.

From circuit analysis, in the time that formula (11) meets, the input power of the first port will be distributed to the second port and the 3rd port, and phase shift is identical.When from the 4th port excitation, power will be distributed to the second port and the 3rd port, but have 180 degree phase differences.In addition,, in the time of integrated two kinds of coupled structures, circuit can obtain wide stopband filter response.Due to two kinds of coupled structure compactnesses, historical facts or anecdotes has showed the Miniaturization Design of overall hybrid ring circuit.

Embodiment 1

In the present embodiment, as shown in Figure 7, design parameter is a kind of miniaturization hybrid ring circuit structure with filter function: the wide stop-band frequency of filtering hybrid ring is at 470MHz, and the relative dielectric constant of backing material is 3.38, and thickness is 0.81mm.The physical dimension of filtering hybrid ring is: L ₁=L ₃=30.8mm, L ₂=L ₄=5.3mm, w=0.3mm, C=8pF, C _e=1.5pF.The size of whole filtering hybrid ring is 37.1mm × 45.6mm(or 0.095 λ _g× 0.117 λ _g, λ _gthe wavelength corresponding to centre frequency of passband), only account for 4.6% of common hybrid ring size.

As shown in Figure 8, be the emulation of this embodiment and the first port of actual measurement and the 4th interport isolation, exceed 50dB at the isolation at centre frequency place, in broad frequency range, remain on 30dB.

Fig. 9 (a), Fig. 9 (b), Fig. 9 (c) are emulation and the measured value of this embodiment in the time of push-push operation, now can obtain good merit point performance and band-pass response.Centre frequency is 470MHz, and fractional bandwidth is 13%, has produced 2 transmission zeros in passband edge.In passband, point power such as the second port and the 3rd port, corresponding S parameter is respectively: S ₂₁=-4.35, S ₃₁=-4.32dB, Insertion Loss ≈ 1.3dB.Stopband is spread to 2.4GHz(5 subharmonic place), isolation exceedes 20dB.The actual measurement of amplitude and phantom error are less than 0.1dB, and in band, return loss is better than 20dB, and the actual measurement of phase place and phantom error difference are less than 3 degree.

Figure 10 (a), Figure 10 (b), Figure 10 (c) are emulation and the measured value of this embodiment in the time of anti-phase work.Actual measurement S parameter is: S ₂₄=-4.36dB, S ₃₄=-4.38dB.S parameter (the S of the second port and the 3rd port ₂₁and S ₃₁) the not enough 0.1dB of gap.Wide stopband isolation exceedes 20dB, reaches 5 subharmonic positions.In band, return loss is better than 20dB, and the phase difference of the second port and the 3rd port almost reaches 180 degree.

Above-described embodiment is preferably execution mode of the utility model; but execution mode of the present utility model is not limited by the examples; other any do not deviate from change, the modification done under Spirit Essence of the present utility model and principle, substitutes, combination, simplify; all should be equivalent substitute mode, within being included in protection range of the present utility model.

Claims (5)

1. the miniaturization hybrid ring with filter function, comprise upper strata microstrip structure, intermediate medium substrate and underlying metal floor, it is characterized in that, described upper strata microstrip structure comprises the first port, the second port, the 3rd port, the 4th port, the first filtering K converter, the second filtering K converter, the 3rd filtering K converter and-filtering K converter, wherein the first filtering K converter is connected between the first port and the second port, the second filtering K converter is connected between the first port and the 3rd port, the 3rd filtering K converter is connected between the 3rd port and the 4th port, filtering-K converter is connected between the second port and the 4th port.

2. a kind of miniaturization hybrid ring with filter function according to claim 1, it is characterized in that, described first, second, third filtering K transformer configuration is identical, and the short-circuited transmission line that has loaded capacitor C by 2 two ends forms, and 2 short-circuited transmission lines are folded into L-type, by capacitor C _eunsymmetric structure in series.

3. a kind of miniaturization hybrid ring with filter function according to claim 1, is characterized in that, described filtering-K converter is made up of the short-circuited transmission line of 2 two ends loading capacitance C, and 2 short-circuited transmission lines be folded into U-shaped, by capacitor C _eformation symmetrical structure in parallel.

4. a kind of miniaturization hybrid ring with filter function according to claim 1, is characterized in that, forms filtering K converter identical with the parameter of the short-circuited transmission line of formation filtering-K converter, and the length of described short-circuited transmission line is 36.1mm, and width is 0.3mm.

5. a kind of miniaturization hybrid ring with filter function according to claim 1, is characterized in that, the relative dielectric constant of described intermediate medium substrate is 3.38, and thickness is 0.81mm.