CN104600411A - Method for realizing adjustability of coupling degree of coupler - Google Patents

Abstract

Disclosed is a method for realizing adjustability of the coupling degree of a directional coupler. A concentration element resistor and a capacitor are added at a coupling end of the coupler, and the impedance of a port is changed, so that the coupling degree is changed. According to the method, the strip-line directional coupler with the adjustable coupling degree is designed and mainly comprises a coupler shell 31, two same dielectric plates 41, a 50-ohm chip resistor 53, an adjustable chip capacitor 52 and a capacitance adjusting metal rod 32. The resistor 53 and the capacitor 52 which are parallelly connected in a group are added on the inner side of a microstrip line in front of the coupling end, and an open-circuit node 51 is added on the inner side of a microstrip line in front of an isolation end in order to improve isolation. The impedance of the coupling port is changed by adjusting capacitance through the metal rod 32, and the coupling degree and the isolation of the coupler are changed, so that the coupling degree of the coupler can be adjusted.

Description

A kind ofly realize the adjustable method of the coupler degree of coupling

Technical field

This patent relates to a kind of microwave device directional coupler.

Background technology

Directional coupler is the directive coupling power of a kind of tool (distribution) element.It is a kind of four port elements, usually by being called that two sections of transmission line combination of direct-through line (main line) and coupling line (by-pass) form.A kind of operation principle of directional coupler as shown in Figure 1, by certain coupling mechanism (such as gap, hole, coupling line segment etc.), a part for direct-through line power (or whole) is coupled in coupling line between direct-through line and coupling line, and require that power is only transmitted to a certain output port in coupling line, another port then inactivity exports.If direction of wave travel becomes contrary with original direction in direct-through line, the port that then in coupling line, the output port of power and inactivity export also can change thereupon, that is, the coupling (distribution) of power is directive, is therefore called directional coupler (directional coupler).

In order to the quality weighing a directional coupler performance needs to introduce some performance parameters.

Degree of coupling C is defined as the logarithm of input power P 1 and the ratio of coupled end power P 3, namely

$C\left(\mathrm{dB}\right)=10\log \frac{P_3}{P_1}$

Directivity D is defined as the logarithm of the power output P3 of coupled end and the ratio of the power output P4 of isolation end, namely

$C\left(\mathrm{dB}\right)=10\log \frac{P_3}{P_4}$

Isolation I is defined as the logarithm of input power P 1 and the ratio of isolation end power P 4, namely

$I\left(\mathrm{dB}\right)=10\log \frac{P_1}{P_4}=C\left(\mathrm{dB}\right)+D\left(\mathrm{dB}\right)$

Insertion loss IL is defined as the logarithm of input power P 1 and the ratio of straight-through end power P 2, namely

$\mathrm{IL}=10\log \frac{P_1}{P_2}$

Bandwidth of operation refers to the operating frequency range of the directional coupler when the technical indicator such as degree of coupling C, directivity D, isolation I, insertion loss IL meets design requirement.

Traditional directional coupler dimensional structure is once after determining, the corresponding degree of coupling of coupler and isolation are just determined thereupon.If find in test process that a certain parameter can not meet index request, just must open coupler shell and carry out internal structure adjustment, debug process is quite complicated loaded down with trivial details.Secondly, the versatility of traditional directional coupler is strong, and due to the restriction of structure, each coupler can only be used in the product of specific degree of coupling requirement.If need the coupler of the specific degree of coupling of another one, just directional coupler must be redesigned.

Summary of the invention

The present invention well compensate for the deficiency of above-mentioned conventional coupler, devises the strip line directional coupler that a kind of degree of coupling is adjustable.

Technical scheme is: the strip line directional coupler that this degree of coupling is adjustable, mainly comprises fluid coupling shell, two blocks of identical dielectric-slabs, the Chip-R of 50 ohm, the Metallic rod of an adjustable patch capacitor and control capacittance.Resistance and the electric capacity of one group of parallel connection are added in microstrip line side before coupled end output port, and in order to improve isolation, before isolation end, open circuit detail is added in microstrip line side.By Metallic rod capacitance value, change the impedance of coupling port, the degree of coupling and the isolation of coupler change, thus realize the adjustable of the coupler degree of coupling.

Accompanying drawing explanation

Fig. 1 is the fundamental diagram of general directional coupler;

Fig. 2 is the fundamental diagram of the adjustable strip line directional coupler of the degree of coupling of design;

Fig. 3 is the stereoscopic figure of the adjustable strip line directional coupler of the degree of coupling of design;

Fig. 4 be the adjustable strip line directional coupler of the degree of coupling of design perspective interior view;

Fig. 5 is cross section, the inside vertical view of the adjustable strip line directional coupler of the degree of coupling of design;

Fig. 6 is the degree of coupling change curve of the adjustable strip line directional coupler of the degree of coupling of design;

Embodiment

For making object, operation principle, the advantage clear and definite more of the design, below in conjunction with embodiment, accompanying drawing is described further the design.

What the design adopted is three rank strip line directional couplers, and employing is parallel strips coupled modes, and object is that its schematic diagram as shown in Figure 2 in order to obtain wider bandwidth of operation.The first step designs the qualitative coupler of three rank strip lines that a degree of coupling is-10dB, in order to improve directivity, adding a micro-band open circuit detail 51, make the directivity of coupler be greater than 25dB before coupler isolated port.Then the Chip-R 53 of a 50ohm in parallel and an adjustable patch capacitor 52 before the coupling port of coupler, the value of patch capacitor is regulated by metal thin bar 32, change the impedance of coupler coupling port, the degree of coupling and the isolation of coupler change, thus realize the adjustable of the coupler degree of coupling.

The stereoscopic figure of the qualitative coupler of strip line of design as shown in Figure 3, comprises metal shell 31, the screw 34 of adjustment Metallic rod 32, four sub-miniature A connectors 33 and six fixing metal shells.Inner stereogram as shown in Figure 4, mainly comprises the coupling line 42 in the middle of two blocks of FR4 dielectric-slabs 41 and dielectric-slab bonded.Dielectric-slab extracts cubic root the groove of body near coupler coupling port, facilitates the interpolation of adjustable patch capacitor and regulates the installation of Metallic rod.Sub-miniature A connector outside metal-back is connected to four ports of coupling line 42, provides input and output energy.Fig. 5 represents the vertical view of the inner sectional view of coupler, mainly comprises the micro-band being added on isolation end and to open a way detail 51, be added on the parallel connection of coupled end adjustable patch capacitor 52 and the Chip-R 53 of 50ohm, and be all connected to earth terminal 54.One end of metal sense 32 is connected to adjustable patch capacitor, the other end stretches out metal shell, in outside by the sympathetic capacitance that can regulate interior patches electric capacity of rotating metallic, change the impedance of coupler coupled end, the degree of coupling and the isolation of coupler change, thus realize the adjustable of the coupler degree of coupling.

The operating frequency of the design is at 1.8GHz-2.2GHz, and the excursion of the degree of coupling is-13dB to-22dB, and as shown in Figure 6, isolation is greater than 10dB, and insertion loss is less than 0.5dB.Certain utilization the method also can design the variable coupler being operated in other frequency ranges.

The strip line directional coupler that the degree of coupling of the design is adjustable has following characteristics:

Structural design is flexible, installs easily fixing, does not need special erecting tools.

Debug process is simply easy, only needs the adjustment Metallic rod of revolving outer just can realize the adjustment of the degree of coupling.

Be more than the description to the present invention and embodiment thereof provided to the engineers and technicians being familiar with field of the present invention, these descriptions should be considered to be illustrative, but not determinate.Engineers and technicians the thought accordingly in invention claims can do concrete operation and implement, and naturally also can do a series of change according to the above to embodiment.The content be not described in detail in specification of the present invention belongs to the known technology of professional and technical personnel in the field.

Claims (5)

1. realize the method that the coupler degree of coupling is adjustable, add lumped elements resistance and electric capacity in coupler coupled end, change port Impedance, reach the object changing the degree of coupling.Design the strip line directional coupler that a kind of degree of coupling is adjustable, mainly comprise fluid coupling shell 31, two pieces of identical Chip-R 53, adjustable patch capacitors 52 of dielectric-slab 41,50ohm and the Metallic rod 32 of control capacittance.It is characterized in that: the capacitance being regulated patch capacitor 52 by Metallic rod 32, change the impedance of coupling port, the degree of coupling and the isolation of coupler change, thus realize the adjustable of the coupler degree of coupling.

2. the directional coupler that the degree of coupling as claimed in claim 1 is adjustable, it is characterized in that: fluid coupling shell 31 is opened a circular hole, Metallic rod 32 is connected on adjustable patch capacitor 52 by circular hole, regulates Metallic rod 32 can change the capacitance of interior patches electric capacity 52.

3. the directional coupler that the degree of coupling as claimed in claim 1 is adjustable, it is characterized in that: before 50ohm Chip-R 53 and adjustable patch capacitor 52 are connected in parallel on coupler coupling port, one end is connected to microstrip line 42, the other end is connected to ground plate 54, and ground plate 54 is connected to ground, the back side by Via Design.

4. the directional coupler that the degree of coupling as claimed in claim 1 is adjustable, is characterized in that: before isolated port, add a micro-band open circuit detail 51, object is the isolation in order to improve coupler, improves directivity.

5. the directional coupler that the degree of coupling as claimed in claim 1 is adjustable, it is characterized in that: the impedance changing coupler coupling port, realize the adjustable of the degree of coupling, be not only applicable to strip line directional coupler, be equally applicable to microstrip line directional coupler, and also can realize the adjustable of the degree of coupling preferably at other working frequency range.