KR101015545B1 - Dc blocking device using slow wave structure - Google Patents

Abstract

PURPOSE: A DC blocking device using a slow wave structure is provided to minimize the restriction due to the space in attaching the DC blocking device. CONSTITUTION: A DC(Direct Current) blocking device comprises a connector part(450) and an insertion conductor(412). The connector portion includes an internal conductor, an external conductor(402), a connector housing(404), and a coupling plate(406). An RF(Radio Frequency) signal is applied to the internal conductor. A groove is formed inside the internal conductor. The outer conductor is electrically connected to the earth. The insertion conductor is inserted into the groove of the internal conductor. The insertion conductor is electrically separated with the internal conductor. In the insertion conductor, a protruded part(412a) and groove(412b) are repetitively installed.

Description

DC Blocking Device Using Slow Wave Structure}

The present invention relates to a DC blocking device, and more particularly, to a DC blocking device used in a mobile communication system such as a tower mounted amplifier (TMA).

The mobile base station amplifies a signal to be transmitted by a high power amplifier located in the base station when transmitting a signal, and then transmits a transmission signal to an antenna installed in a tower through a feed cable, and the antenna installed in the tower radiates a transmission signal. In addition, the mobile communication base station system amplifies a weak reception signal by receiving a signal from the antenna installed in the tower and transmitting the signal to a low noise amplifier in the base station through a feed cable.

In such a mobile communication base station system, the base station system and the antenna are generally installed at a considerable distance, and there is a problem that the signal is attenuated while the transmission signal and the reception signal are transmitted through the feed cable. When the base station system and the antenna reaches several tens of meters, more than 3dB of the input signal may be attenuated, which may cause a decrease in reception sensitivity due to a relative increase in reception.

In order to solve this problem, when the antenna and the base station are installed far away, the use of a TMA having a transmission / reception filter and an amplifier and installed adjacent to the antenna is being changed.

The TMA is provided with an RF signal and a DC power signal together, and needs to be transmitted separately from the RF signal and the DC power signal. Of course, a mobile communication device such as a repeater other than the TMA also needs a device that separates and transmits the RF signal and the DC power signal. In addition, many RF equipments need to block DC signals even if they are not devices such as TMA. To this end, DC blocking devices using capacitive coupling have been developed.

These devices are not required when installing the RF preference and DC power line separately, but this is a difficult and costly construction work, in order to separate and transmit the RF signal and DC power signal through one line. DC blocking devices have been developed.

 The DC blocking device is a device that functions to block a DC signal when receiving an RF signal and a DC power signal at the same time. Such a DC blocking device and a circuit diagram thereof are shown in FIGS. 1 to 3.

1 is a diagram illustrating a circuit configuration of a general DC blocking device.

Looking at the operation of the DC blocking device with reference to Figure 1, the RF signal and the DC power signal is input to the terminal (a). Of the RF signal and the DC power signal, the DC power signal cannot pass through the capacitor C1, and the RF signal passes through the capacitor and is output to the terminal (b).

Meanwhile, the RF signal of the RF signal and the DC power signal cannot pass through the inductor, and the DC power signal is output to the terminal (c) through the inductor L1. If only DC blocking is the purpose, the terminal b coupled with the inductor may be omitted.

As such, the DC blocking device functions to separate the DC power signal and the RF signal into different paths by a combination of an inductor and a capacitor. Of course, a DC blocking device that blocks only the DC signal without providing a separate path for the DC signal is used, in which case no inductor is provided.

2 to 3 are exploded perspective views and cross-sectional views of a conventional DC blocking device.

2 and 3, a conventional DC blocking device is formed on a connector including an inner conductor 100, an outer conductor 102, a housing 104, and a coupling plate 106, and formed on an inner conductor 100. It may include a branch groove 108, the insertion groove 110 and the insertion conductor 112 is inserted into the insertion groove (110).

  An RF signal is applied to the inner conductor 100, and the outer conductor 102 is electrically connected to ground.

Branch conductors 108 and insertion grooves 110 are formed in the inner conductor 100. An inductor (not shown) is electrically connected to the branch groove 108, and the DC power signal is output through the inductor electrically connected to the branch groove 108.

In addition, an insertion conductor 112 is inserted into the insertion groove 110. The insertion conductor 112 is not electrically connected to the inner conductor 100 and is inserted at a predetermined distance. Capacitance is formed between the inner conductor 100 and the insertion conductor 112, and by coupling, the RF signal is coupled to the insertion conductor and output to the outside.

In such a conventional DC blocking device, in order for proper coupling between the inner conductor and the insertion conductor 112 to be achieved, the length of the section in which the coupling is performed (that is, the length of the insertion conductor) should be set to 1/2 of the wavelength.

Therefore, the length of the coupling section becomes longer as the frequency decreases. In the low frequency band (850 to 900 MHz), the length of the coupling section becomes longer, which increases the size of the DC blocking device and increases the density of the mobile communication equipment. There was a problem of being spatially restricted when mounted.

In the present invention, to solve the problems of the prior art as described above, to propose a DC blocking device that can be manufactured in a more compact structure.

Another object of the present invention is to propose a DC blocking device capable of minimizing spatial constraints when mounted in mobile communication equipment.

Still another object of the present invention is to propose a structure in which proper coupling can be made even if the length of the coupling portion in the DC blocking device is reduced.

Other objects of the present invention will be readily apparent to those skilled in the art through the following examples.

In order to achieve the above object, according to an aspect of the present invention, the RF signal is applied, the inner conductor is formed therein; An outer conductor electrically connected to ground; And an insertion conductor inserted into a groove of the inner conductor and electrically spaced from the inner conductor, wherein the insertion conductor is provided with a DC blocking device using a delayed wave structure in which protrusions and grooves are repeated.

Coupling from the inner conductor to the insertion conductor takes place and the coupling frequency is determined by the size difference of the protrusions and grooves and the number of repeated protrusions and grooves.

The cross section of the protrusion may have a rectangular shape.

An inductor is coupled to the inner conductor. When a DC signal and an RF signal are applied to the inner conductor, the DC signal is provided in a path in which the inductor is coupled, and the RF signal is coupled from the inner conductor to the insertion conductor.

According to the present invention, a spatial restriction can be minimized when the DC blocking device is mounted on a mobile communication device, and an appropriate coupling can be made even if the length of the coupling part in the DC blocking device is reduced.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the DC blocking device using a slow wave structure according to the present invention.

4 is an exploded perspective view of a DC blocking device using a delay wave structure according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view of a DC blocking device using a delay wave structure according to an embodiment of the present invention. Figure is shown.

4 and 5, a DC blocking device according to an embodiment of the present invention includes a connector unit including an inner conductor 400, an outer conductor 402, a connector housing 404, and a coupling plate 406 ( 450 and an insertion conductor 412, and an insertion groove 410 is formed in the inner conductor 400.

In FIG. 4, the inner conductor 400 to which a signal is applied is an inner conductor of a connector. However, the inner conductor 400 of the connector may be an inner conductor of a general transmission line. It will be apparent to those skilled in the art.

An RF cable is coupled to the connector 450, and an RF signal and a DC signal are supplied from the RF cable. In one example, the RF cable may be a coaxial cable. The DC signal may be a signal for powering a modem or other device mounted on a TMA or repeater, or may be a signal for bias of another kind.

The inner conductor 400 and the outer conductor 402 function as a signal transmission path, the RF signal and the DC signal are applied to the inner conductor 400 and the outer conductor 402 provides the ground potential. The inner conductor 400 and the outer conductor 402 may have a cylindrical shape.

Although not shown in FIG. 4, an inductor (not shown) may be coupled to the entrance of the internal conductor 400 to transmit the DC signal through a separate path. For example, if the DC signal is a power signal of a specific device, the inductor may be coupled to the internal conductor 400 to provide the DC power signal to the device through the inductor. If you want to block the unwanted DC bias can be made of a structure as shown in FIG.

The insertion conductor 412 is inserted into the insertion groove 410 formed in the inner conductor. Insert conductor 412 is electrically connected to an RF signal output terminal (not shown).

As shown in FIGS. 4 and 5, the insertion conductor 412 is inserted at a predetermined distance from the inner conductor 400. A dielectric may be filled between the insertion conductor 412 and the inner conductor, and a general air layer may serve as the dielectric. It will be apparent to those skilled in the art that Teflon dielectric may be used and dielectrics of various materials may be used when the dielectric is filled.

 An electromagnetic coupling phenomenon occurs between the inner conductor 400 and the insertion conductor 412, and the RF signal applied to the inner conductor 400 is coupled and output from the inner conductor 400 to the insertion conductor 412. . That is, the RF signal applied to the inner conductor 400 is coupled to the insertion conductor 412 but the DC signal is blocked without being coupled.

According to a preferred embodiment of the present invention, the insertion conductor 412 in which the coupling takes place has a delayed wave structure. The delayed wave structure is a structure in which a periodic pattern is repeated, and a structure for controlling the speed of a signal in a transmission line, but such a delayed wave structure is applied to the insertion conductor 412 of the present invention.

As shown in FIGS. 4 and 5, the insertion conductor 412 has a structure in which the protrusion 412a and the groove 412b are periodically repeated. 4 and 5 illustrate a structure in which a rectangular protrusion is periodically repeated in cross section, but it will be apparent to those skilled in the art that the protrusion may be variously set. For example, a triangular cross section may be provided so that the cross section of the insertion conductor may have a sawtooth shape.

)의 1/2

/2 길이로 설정되어야 한다. 예를 들어, 850MHz ~ 900MHz 대역의 RF 신호가 사용될 경우, 커플링이 일어나는 부분의 길이는 약 42mm로 설정되어야 하나, 본 발 명에 의한 지연파 구조가 이용될 경우 이보다 작은 길이로 삽입 도체의 길이를 소형으로 구현할 수 있다. As such, the formation of the insertion conductor 412 in a delayed wave structure is intended to implement a smaller length of the insertion conductor. As described above, the length of the portion of the coupling between the inner conductor 400 and the insertion conductor 412 is the center frequency wavelength (

1/2 of)

It should be set to a length of / 2. For example, when an RF signal in the 850 MHz to 900 MHz band is used, the length of the coupling portion should be set to about 42 mm, but if the delay wave structure according to the present invention is used, the length of the insertion conductor is smaller than this. Can be implemented in a small size.

In the delayed wave structure as shown in FIG. 4, as the difference between the diameter of the protruding portion and the diameter of the groove portion and the number of repetition of the protruding portion and the groove portion are increased, the frequency band to be coupled decreases.

That is, when the delayed wave structure according to the present invention is applied to the insertion conductor 412, even if the length of the insertion conductor is smaller in the same band, appropriate DC blocking and RF signal coupling can be achieved.

FIG. 6 is a diagram illustrating the reflection loss when the insertion conductor having a general line shape is used and the reflection loss when the insertion conductor having a delay wave structure according to the present invention is used.

In FIG. 6, the insertion conductor of the delayed wave structure has a diameter of 2.9 mm for the protrusion, the diameter of the groove is 1 mm, and the number of the protrusions and the grooves is set to 27. Although a zero point is formed at about 1.14 GHz, a zero point is formed at about 1.83 GHz when a typical line-shaped insertion conductor is used.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

1 is a diagram illustrating a circuit configuration of a general DC blocking device.

2 to 3 is an exploded perspective view and a cross-sectional view of a conventional DC blocking device.

4 is an exploded perspective view of a DC blocking device using a delay wave structure according to an embodiment of the present invention.

5 is a cross-sectional view of a DC blocking device using a delay wave structure according to an embodiment of the present invention.

Fig. 6 is a diagram showing the reflection loss when the insertion conductor of the general line shape is used and the reflection loss when the insertion conductor of the delay wave structure according to the present invention is used.

Claims (4)

An inner conductor to which an RF signal is applied and a groove is formed; An outer conductor electrically connected to ground; And Includes an insertion conductor inserted into the groove of the inner conductor and electrically spaced from the inner conductor, The insertion conductor is a DC blocking device using a delayed wave structure, characterized in that the projecting portion and the groove is repeated structure. The method of claim 1, Coupling is performed from the inner conductor to the insertion conductor, and the coupling frequency is determined by the difference in size of the protrusions and grooves and the number of repeated protrusions and grooves. . The method of claim 1, Cross section of the protrusion is a DC blocking device using a delay wave structure, characterized in that the rectangular shape. The method of claim 2, An inductor is coupled to the inner conductor, and when a DC signal and an RF signal are applied to the inner conductor, the DC signal is provided in a path in which the inductor is coupled, and the RF signal is coupled from the inner conductor to the insertion conductor. DC blocking device using a delayed wave structure characterized in.

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