KR20010094508A - The Varactor-Tuned Microstrip Ring Resonator with Harmonic Suppression and Its Manufacturing Method - Google Patents

Abstract

PURPOSE: A varactor synchronous microstrip ring band-pass wave filter having harmonic wave suppression characteristics and a manufacturing method thereof are provided to suppress a spurious signal within a micro wave amplifier by connecting a varactor diode to a ring resonator. CONSTITUTION: A mode suppression microstrip ring resonator is comprised of coupled lines and a slit. An interior of the ring resonator composed of the coupled lines(7) having an electric length(θ) and the slit, includes a low-pass wave filter with the mode suppression ring resonator. A feeder and a normal resonator part maintain characteristic impedance. The low pass wave filter inserted in the ring resonator is comprised of a parallel capacitance part having a low impedance(Z1), a narrow part having a serial inductance possessing a high impedance(Zh), and a part having a parallel capacitance.

Description

Varactor-tuned microstrip ring resonator with harmonic suppression and its manufacturing method

The present invention relates to a varactor tuned microstrip ring bandpass filter and a method of manufacturing the same. More specifically, a lowpass filter is inserted into a ring resonator constituting the bandpass filter, and a slit is provided to the ring resonator. The present invention relates to a varactor tuned microstrip ring bandpass filter having a harmonic suppression characteristic that can be adjusted by connecting a varactor diode and a method of manufacturing the same.

Recently, wireless communication is showing rapid development centering on mobile communication.

Increasingly, users of wireless communication are demanding miniaturization and lightening of their own terminals as well as improving the quality of communication services.

In addition, as the frequency band used in wireless communication shows a tendency to move to a higher band, development of various RF technologies suitable for this is required.

Monolithic Microwave Integrated Circuit (MIC) technology, which has been accelerated in research and development since the 1980s, is a method of integrating ultra-high frequency circuits on a single semiconductor substrate and has a wide range of applications for high-frequency circuit implementation.

In order to monolithic MIC circuits, a planar structure is required, so transmission lines such as slotlines and coplanar waveguides, which are planar microstrips or single planar structures, must be used.

Microstrip ring resonators with no open-end effects compared to linear resonators have been widely used to measure the properties of materials such as dispersion, phase velocity, Q-factor and dielectric constant.

Recently, however, as a device of the microwave single integrated circuit, research on microwave circuits using a ring resonator has been increasing.

In particular, the bandpass filter using a microstrip ring resonator has a lot of research because of the advantage that the circuit shape is simple.

Dual-mode microstrip ring bandpass filter using split ring resonance mode, two-stage selector tuning ring bandpass filter composed of two ring resonators, microstrip ring bandpass filter suppressing harmonics As various studies have been published, the applicability in the next generation wireless communication system is high.

The general structure of the microstrip ring bandpass filter will be described below with reference to the accompanying drawings.

1 is a conventional dual mode microstrip ring bandpass filter, and FIG. 2 is a conventional two-stage microstrip ring bandpass filter. First, referring to FIG. 1, a conventional microstrip ring bandpass filter is input. It consists of a line (2), a ring resonator (1), an output line (3) and a stub (5) for coupling the spacing (4) and two degenerate mode couplings.

The ring resonator (1) in that the resonance when the average circumference of the ring is to be an integral multiple of the wavelength occurs in vitro which is represented by 2πr = nλ _g (1).

The stub 5 induces a bandpass filter characteristic by adjusting the degree of splitting of the resonance mode.

However, since the input line and the output line are fed at a 90 degree difference, the insertion loss and the return loss are large in the first resonance mode.

As described above, the conventional two-stage ring bandpass filter coupled with two ring resonators in order to avoid insertion loss and reflection loss in the first resonance mode due to the 90 degree difference feed structure is formed as shown in FIG.

However, since the coupling capacitance between the input line and the output line and the ring resonator is small, it is difficult to use it as a band pass filter.

The insertion loss and reflection loss of the ring bandpass filter are large because the coupling structure of the ring resonator constituting the bandpass filter does not support the maximum coupling. Recently, a new ring resonator coupling structure has been proposed to increase the coupling efficiency of such a ring resonator.

In addition, a mode suppression ring resonator is proposed to suppress unwanted modes and to support only desired resonance modes.

The newly proposed ring resonator is as follows.

3 is a microstrip ring resonator composed of two couple lines and a slit, and FIG. 4 is a microstrip mode suppression ring resonator. First, referring to FIG. 3, the ring resonator is an input line 2. And a ring resonator 6 with a slit, an output line 3 and two pairs of couple lines 7 surrounding an open ring with an arc length corresponding to an angle θ at an interval, inside and outside. .

Therefore, the coupling effect can be maximized, and a certain frequency is suppressed by the coupling structure.

Referring to FIG. 4, a portion of the ring resonator 1 is replaced with a low pass filter 8 to suppress unwanted modes.

Recently, a study of a two-stage coupling bandpass filter having harmonic suppression characteristics has been published by applying the mode suppression ring resonator.

This is as follows.

5 is a microstrip multistage coupling bandpass filter with harmonics suppressed. Distributed elements used in the ultra-high frequency band have unnecessary harmonic components unlike the concentrated elements. Such harmonic components were suppressed by applying the mode suppression ring resonator 9.

An object of the present invention is to give a slit to a ring of a band pass filter and to reduce the loss by lengthening a couple line inside and outside the ring, and to a low band inside a ring resonator having strong attenuation characteristics according to two couple lines. By applying a pass filter to suppress harmonics, attenuate the mode suppressed by the λ / 4 open stub on the input and output lines, and connect the varistor diodes to adjust the pass band of the designed band pass filter to adjust the microwave and millimeter wave circuit. The present invention provides a varistor tuned microstrip ring bandpass filter that can be applied to the present invention.

1 is a conventional dual mode microstrip ring bandpass filter

2 is a conventional two-stage microstrip ring bandpass filter

3 is a microstrip ring resonator consisting of two couplelines and slits

4 is a microstrip mode suppression ring resonator.

5 is a harmonic-suppressed microstrip multistage coupling bandpass filter

Figure 6 is a mode inhibiting microstrip ring resonator composed of the present invention coupleline and slit

Figure 7 shows the present invention harmonics suppressed microstrip ring bandpass filter

Fig. 8 is a varactor tuned microstrip ring bandpass filter having the present inventors harmonic suppression characteristics.

9 is a graph illustrating simulation results of a microstrip ring bandpass filter having harmonic suppression characteristics of FIG.

FIG. 10 is a graph showing measurement results of a microstrip ring bandpass filter having harmonic suppression characteristics of FIG.

11 is a graph of simulation results for insertion loss of the present invention

12 is a graph of the measurement results for the insertion loss of the present invention

Figure 13 is an exemplary view showing the manufacturing process of the ring bandpass filter on the dielectric substrate of the present invention

<Description of the symbols for the main parts of the drawings>

1: ring resonator 2: input line

3: output line 4: coupling gap

5: coupling stub 6: ring resonator with slit

7: Couple line 8: Low pass filter to a part of ring resonator

9 mode suppression ring resonator 10 ring with slit with integrated lowpass filter

11 coupling distance 12 lambda / 4 opening stub

13: varistor diode

w: width of couple line

ψ: reference angle for representing the slit of the ring

θ: angle for indicating electrical length of couple line

Hereinafter, with reference to the accompanying drawings with respect to the configuration and operation of the embodiment for achieving the object of the present invention will be described.

FIG. 6 is a mode inhibiting microstrip ring resonator composed of a couple line and a slit of the present invention, and a low pass filter is formed inside a ring resonator composed of a couple line 7 and a slit having an electrical length θ such that a low pass filter is formed. The furnace and the general resonator part retained characteristic impedance, and the lowpass filter inserted inside the ring resonator has a parallel capacitance part with low impedance (Zl), a narrow part with series inductance with high impedance (Zh), and again parallel capacitance. Part consists of three steps.

The mode of suppression varies depending on where the lowpass filter is located inside the ring resonator.

7 is a ring bandpass filter designed by applying a mode inhibiting microstrip ring resonator composed of the coupleline 7 and a slit as a microstrip ring bandpass filter suppressing harmonics of the present invention.

A ring 10 having a slit with integrated lowpass filter is located with a coupling gap 11 and has a new coupling structure between the input line and the output line, the feed line and the ring resonator. In addition, the λ / 4 open stub 12 is positioned at regular intervals between the input line and the output line, which serves to attenuate unnecessary components.

FIG. 8 is a varactor tuned microstrip ring bandpass filter having harmonic suppression characteristics according to the present invention, wherein a slit is provided at a position where? = 90 ° in a resonator constituting the ring bandpass filter having harmonic suppression characteristics. 2, a mode suppression ring resonator 10 which suppresses a specific mode and causes resonance, a coupling interval 11 between the ring resonator, a couple line 7, It consists of a λ / 4 open stub 12 and a varistor diode 13 located on the output line.

With respect to the present invention having the above configuration, RF Circuit Design Tool (CAD Tool), HP ADS ver. The simulation result of 1.1 and the measurement by the network analyzer (Network Analyzer) were measured.

9 is a simulation result of the microstrip ring bandpass filter having the harmonic suppression characteristic of FIG. 7.

FIG. 10 is a measurement result of the microstrip ring bandpass filter having the harmonic suppression characteristic of FIG.

11 is a graph of simulation results for insertion loss of the present invention.

12 is a graph of a measurement result for insertion loss of the present invention.

The circuit manufacturing process on the dielectric substrate of the ring bandpass filter as described above is as follows.

FIG. 13 is an exemplary diagram illustrating a process of manufacturing a ring bandpass filter on a dielectric substrate of the present invention, in which a substrate in which the dielectric 11 is filled in the conductor 9 is cut to a desired circuit size (L100). .

When the substrate is cut in the process (L100), the TRP photoresist 7 solution is applied thinly (L200).

When the TRP photoresist 7 is applied on the substrate in the process (L200), the negative film 12 having the pattern of the ring resonator is placed on the substrate and then floated on the ultraviolet exposure unit (L300).

The substrate exposed to ultraviolet rays in the process (L300) is put into the developer, the portion of the ultraviolet rays are left as a circuit and the remaining portions are erased (L400).

When the circuit of the desired pattern is left on the substrate in the process (L400), and put in the ferric chloride solution, the conductor 9 portion exposed to ultraviolet light remains a ring circuit and the remaining conductor 9 portion is etched.

In the process L500, the varistor diode is bonded to the slit portion of the ring resonator over the circuit of the substrate.

Through all the above processes, a varactor tuned microstrip ring bandpass filter is produced in which harmonics have suppression characteristics as intended by the present invention.

As can be seen from the above description, the present invention connects a mode suppression ring resonator in which a low pass filter is inserted into the ring resonator to suppress harmonic components in two stages, and improves the coupling efficiency of the input and output sections. By applying a structure that improves insertion loss and return loss by slitting and extending the couple line inside and outside the ring, the spurious signal in the microwave amplifier is a filter that does not pass unwanted harmonics in the micro and millimeter circuits. There is an effect that can be applied to suppress the. In addition, the bias voltage of the varistor diode can be adjusted for frequency tuning, which provides flexibility in circuit implementation.

Claims (5)

In a microstrip ring bandpass filter comprising an input line, a ring resonator, and an output line, a couple line and a slit having an electrical length θ are formed in the ring resonator, and a mode inhibited low pass filter is formed in the ring resonator. A furnace tuned microstrip ring bandpass filter, characterized in that the furnace and the common resonator portion are configured to maintain characteristic impedance. The low-pass filter inserted into the ring resonator according to claim 1, wherein the low-pass filter has three stages of parallel capacitance having a low impedance Zl, a narrow portion having a series inductance having a high impedance Zh, and a portion having a parallel capacitance again. Varactor tuned microstrip ring bandpass filter, characterized in that consisting of. Mode-inhibited microstrip ring resonator consisting of one couple line and a slit, and a ring having a slit in which the low pass filter is integrated is formed to face each other with a coupling gap, and an arbitrarily set interval for attenuating unnecessary components in the input line and the output line. A varactor-tuned microstrip ring bandpass filter, characterized in that it is configured by λ / 4 open stub. 4. The varistor tuned microstrip ring bandpass filter according to claim 3, wherein the mode suppressing microstrip ring resonator is formed inside the mode suppressing microstrip ring resonator by forming a slit at a position where? = 90 °. CLAIMS 1. A method for manufacturing a micro strip ring band pass filter manufactured by etching a dielectric, the method comprising: cutting a substrate having a dielectric-filled substrate inside a conductor by a desired circuit size; When the substrate is cut in the process, thinly applying the TRP photoresist solution; When the TRP photoresist is applied on the substrate in the coating process, placing a negative film having a pattern of a ring resonator on the substrate and irradiating the ultraviolet light to an ultraviolet exposure machine; The substrate exposed to ultraviolet rays in the exposure process of the exposure machine is placed in a developing solution, and the remaining portion of the ultraviolet rays is left as a circuit and the remaining portions are erased; If the circuit of the desired pattern is left on the substrate during the erasing process, by putting in the ferric chloride solution, the conductor portion exposed to ultraviolet light remains a ring circuit and the remaining conductor portion is etched; And, in the etching process, attaching the varistor diode to the slit portion of the ring resonator on the circuit of the substrate.