KR20060094927A - Filter using ceramic resonator on non-radiative microstrip line - Google Patents

Abstract

The present invention relates to a millimeter wave band wideband filter in which a ceramic resonator is disposed on a non-radiating microstrip line. In detail, the resonant frequency of the filter is determined according to the change in thickness of the ceramic resonator in which the filter is placed, and the selectivity Q value and the cutoff characteristic of the filter are determined according to the change in the distance between the ceramic resonator and the microstrip input / output line. The wide bandwidth of the filter is determined by the coupling coefficient between the ceramic resonator and the resonance period, and the coupling coefficient is determined by the variation of the gap between the ceramic resonator and the resonance period.

According to the fabrication method and structure of the filter, a plurality of ceramic resonators are arranged between the non-radiative microstrip line and the line from one stage to four or more stages, so that the bandwidth is large, the ripple of the pass band is small, and the selectivity Q value is large. It has excellent cut off characteristics, and it is easy to manufacture by attaching ceramic resonator on the PCB board at regular intervals, and it is located on the non-radiating microstrip line between the upper and lower conductor boards with gap of λ / 2 or less. It is a broadband filter for non-radiated microstrip line using ceramic resonator which is characterized by low loss and high efficiency.

Ceramic Resonator, Broadband Filter, Non-Radiant Microstrip Line

Description

Wide band filter for non-radiative microstrip line using ceramic resonator {Filter using Ceramic Resonator on Non-Radiative Microstrip Line}

1: Representative example of implementing a broadband filter using a ceramic resonator in a non-radiative microstrip line

FIG. 2: A drawing arranged on a non-radiating microstrip line using a ceramic resonator

3 is a graph showing the change of the resonance frequency with respect to the thickness change of the ceramic resonator

4 is a graph showing selectivity (Q value) and resonance frequency according to the change of the length of the interval x

5 is a plan view arranged on a non-radiating microstrip line using a two-stage ceramic resonator

6 is a graph showing the relationship between the coupling coefficient and the bandwidth of the interval change of Cg

7 is a plan view arranged on a non-radiating microstrip line using a three-stage ceramic resonator

8: Reflection loss and insertion loss characteristics of the filter using a three-stage ceramic resonator

9 is a plan view of a broadband filter using a four-stage ceramic resonator

10: Return loss (S11) characteristics of the broadband filter using a four-stage ceramic resonator

11: Insertion loss (S21) characteristics of a broadband filter using a four-stage ceramic resonator

<Detailed Description of Details>

1: upper conductor plate, 2: lower conductor plate, 3: dielectric substrate, 4: microstrip line, 5: grounding metal plate, 6: through hole, 7: ceramic resonator

The present invention relates to a broadband filter for a non-radiative microstrip line using a ceramic resonator in the millimeter wave band.

Recently, as the amount of information transmitted through a wireless communication system increases, the need for a large capacity and high speed wireless communication system is increasing. Accordingly, the frequency band used in the communication system is increasing from the microwave band to the millimeter wave band.

In general, the MMIC method can be considered as a technique for processing a band above the microwave, but this technique causes a sudden transmission loss as the frequency used rises to the millimeter wave band. In other words, such a technique is difficult to construct a circuit for a high frequency.

However, the non-radiative microstrip line should be less than half the frequency of the desired frequency of the conductive parallel plate, and a new concept millimeter having low loss characteristics in the millimeter wave band by inserting a dielectric substrate patterned with a microstrip line in between. The transmission line of the wave band can be implemented.

In particular, in the wireless communication transceiver that can be used in the millimeter wave band, the signal of the transmitting end in the same module causes interference to the receiving end.To minimize this, a band pass filter is formed at the transmitting end or the receiving end to minimize the frequency of the transmitting and receiving end. Try to pass only the frequencies you need while reducing interference.

Conventional waveguide-type ceramic filters have high Q and excellent filter characteristics, but are difficult to manufacture due to the difficulty in manufacturing because ceramics must be precisely disposed by processing the inside of the waveguide, which makes it difficult to adjust the characteristics. .

In the case of a filter using a ceramic resonator in a microstrip line, the ceramic resonator is located on the PCB on the ground plate (GND plate), so the distance is too close to the GND plate, and the loss increases, and the Q decreases, so that the overall filter increases. The characteristics of the worse.

Therefore, in order to manufacture a filter which is easy to manufacture, easy to control, low loss and excellent filter characteristics, the method and structure of disposing a plurality of ceramic resonators on a non-radiative microstrip line are proposed for the above reasons. It should be small, excellent in properties, easy to manufacture and inexpensive to make filters.

In order to solve the above problems, the present invention proposes a millimeter wave band filter having the characteristics of a broadband filter by arranging a plurality of ceramic resonators in one stage or more in a ceramic resonator on a non-radiating microstrip line.

Preferably the ceramic resonator is made of a disk having a constant thickness and diameter,

Preferably, the resonant frequency of the first stage of the ceramic resonator is determined according to the thickness change,

Preferably, the Q value changes according to the change in the distance between the ceramic resonator and the microstrip input / output line, and the change of the filter determines the cutoff characteristic of the filter.

Preferably, the interval change between the ceramic resonator and the resonance period is intended to determine the bandwidth of the filter by inducing a coupling coefficient change caused by the resonance mode of TE ₀₁ and higher modes (such as TE _{02 δ} and EH _{11 δ} ).

In the broadband filter for a non-radiative microstrip line using the ceramic resonator (7), the ceramic resonator (7) is made in a disk shape having a constant thickness and diameter,

Preferably, the ceramic resonator 7 is manufactured in a disk shape having a constant thickness and diameter,

Preferably, the first stage ceramic resonator 7 determines the resonant frequency according to the thickness change,

Preferably, since the Q value changes according to the change in the distance between the ceramic resonator 7 and the microstrip input / output line 4, the cutoff characteristic of the filter according to the change is determined,

Preferably, the interval change between the ceramic resonator 7 and the resonator 7 is to determine the bandwidth of the filter by inducing a coupling coefficient change caused by the resonance mode of TE ₀₁ and higher modes (such as TE _02δ and EH _{11 δ} ). do.

The characteristics of the broadband filter include the thickness Ct of the ceramic resonator 7, the diameter R of the ceramic resonator, the distance x length between the non-radiative microstrip line 4 and the ceramic resonator 7, and the ceramic resonator 7 and the resonator 7. The distance between Cg varies greatly.

1 is a representative example of implementing a broadband filter using a ceramic resonator in a non-radiating microstrip line.

According to Fig. 1, the dielectric substrate 3 is inserted between the upper and lower conductor plates 1 and 2 having a spacing of less than half the wavelength of the millimeter wave, that is, the Q band, and the microstrip line 4), the grounding metal plate (5) and the through hole (6) is provided, and the ceramic resonator (7) is disposed from one stage to four or more stages between the microstrip line (4) and the line (4). It is a broadband filter using a ceramic resonator in a non-radiating microstrip line (4).

FIG. 2 is a diagram arranged on the non-radiative microstrip line 4 by using the ceramic resonator 7 in one stage.

Preferably, the thickness Ct of the ceramic resonator 7 is changed to determine the resonance frequency to be used. In this case, the width of the microstrip line may be determined as Sw depending on the frequency used.

According to the first embodiment

In the present invention, the width of the microstrip line is about 1.0 mm for the frequency of the 38 GHz band, and a graph showing the change in resonance frequency with respect to the thickness change of the ceramic resonator of the first stage implemented by FIG. 2 is shown in FIG. 3. .

Referring to FIG. 3, when the thickness Ct of the ceramic resonator 7 is 0.5 mm, the resonant frequency is 40.388 GHz, 0.7 mm is 38.191 GHz, and 0.9 mm is 36.361 GHz.

Therefore, as the thickness of the ceramic resonator increases, the resonance frequency decreases.

According to the second embodiment

2, the selectivity (Q value) and the resonance frequency according to the length of the interval x between the non-radiative microstrip line 4 and the ceramic resonator 7 were confirmed. At this time, the thickness of the ceramic resonator was fixed at 0.68 mm.

4 is a graph showing the selectivity (Q value) and the resonance frequency according to the change in the length of the interval x between the non-radiative microstrip line 4 and the ceramic resonator 7.

According to Figure 4, the length change of the distance x between the non-radiative microstrip line 4 and the ceramic resonator 7 was changed to 0.5mm, 0.6mm, 0.7mm, 0.8mm and 0.9mm, where the resonance frequency is 38.407 GHz, the greater the distance between the resonator 7 and the line 4, the better the selectivity (Q value) appears.

According to the third embodiment,

FIG. 5 shows a plan view on the non-radiative microstrip line 4 using the two-stage ceramic resonator 7.

Preferably, as shown in FIG. 5, the coupling coefficient is changed according to the distance Cg between the ceramic resonator 7 and the resonator 7, and thus, the filter bandwidth is changed.

6 is a graph showing the relationship between the coupling coefficient and the bandwidth by changing the interval of Cg to 1.1mm, 1.3mm, 1.5mm, 1.7mm and 1.9mm in the structure of FIG. In this case, as the distance Cg between the resonator 7 and the resonator 7 increases, the coupling coefficient decreases and the bandwidth decreases.

According to the fourth embodiment,

FIG. 7 shows a plan view of the three-stage ceramic resonator 7 arranged on the non-radiative microstrip line 4.

Preferably, the thickness of the ceramic resonator 7 derived from the first embodiment, the second embodiment, and the fourth embodiment, the distance between the resonator 7 and the line 4, the resonator 7 and the resonator 7 7 was carried out by introducing the optimum parameters for the interval between).

FIG. 8 illustrates the reflection loss and insertion loss characteristics of the filter by the example of FIG. 7. Referring to FIG. 8, when the resonant frequency is 37.2 GHz, the 3 dB bandwidth is about 2.0 GHz, and the skirt characteristic is also good.

According to a fifth embodiment of the present invention,

9 is a plan view preferably arranged on the non-radiative microstrip line 4 using the four-stage ceramic resonator 7.

10 and 11 show the reflection loss (S11) and the insertion loss (S21) showing the characteristics of the filter obtained in the example performed by FIG.

 10 and 11, a resonant frequency of about 36.58 GHz to about 37.68 GHz can be obtained, and the resonant frequency bandwidth is about 1.1 GHz or more, indicating a wide bandwidth, a good skirt characteristic, and a passband ripple. The change is also very stable within 0.5dB.

In the present invention, a wideband filter for a non-radioactive microstrip line using a plurality of ceramic resonators is implemented.

A plurality of ceramic resonators from one stage to four stages are arranged between the non-radiative microstrip line and the line to implement a broadband filter circuit for a wide-band millimeter wave band with a large specific bandwidth and low insertion loss.

When implementing the millimeter wave band filter in the above manner,

By arranging the resonators at regular intervals on the existing dielectric PCB substrate, there is an advantage that can easily implement the filter, it is excellent in mass production.

In addition, since the microstrip line on the dielectric substrate is located at an interval of λ / 2 wavelength or less between the upper and lower conductor plates, the loss at ground (GND) is small, and thus an efficient filter can be realized.

In addition, since the microstrip line maintains sufficient ground (GND) between the upper and lower conductor plates, the Q value is large and the cut off characteristic of the filter is very excellent.

Therefore, in order to manufacture a filter which is easy to manufacture, easy to control, low loss and excellent filter characteristics as described above, a method and structure for arranging a plurality of ceramic resonators on a non-radiative microstrip line were proposed. This small, excellent characteristic, easy to manufacture and inexpensive filter can be made.

Claims (5)

In a broadband filter for a non-radiating microstrip line using a ceramic resonator, The dielectric substrate is inserted between the upper and lower conductor plates with a spacing less than half the wavelength of the used frequency. On the upper surface of the dielectric substrate, a microstrip line, a grounding metal plate, and a through hole are patterned. Broadband filter for non-radiative microstrip line using ceramic resonator characterized by a plurality of ceramic resonators attached between the microstrip line and the line The method of claim 1, The resonant frequency of the broadband filter is determined by the thickness of the ceramic resonator, and the larger the thickness, the higher the resonant frequency is. The broadband filter for the non-radiative microstrip line using the ceramic resonator The method of claim 1, The high selectivity Q value of the broadband filter is determined by the distance between the ceramic resonator and the microstrip line, and the larger the interval, the higher the Q value is. The wideband filter for the non-radiative microstrip line using the ceramic resonator The method of claim 1, The high bandwidth of the broadband filter depends on the coupling coefficient between the ceramic resonator and the ceramic resonator, and the wider the wider the bandwidth, the wider the bandwidth is for the non-radiative microstrip line using the ceramic resonator. Broadband filter for non-radiative microstrip line using ceramic resonator characterized by attaching a plurality of ceramic resonators with four or more stages in order to reduce the wide bandwidth, excellent skirt characteristics of the broadband filter, and the width of the ripple variation of the pass band.

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