KR20130084865A - Dual band rod antenna and mobile device comprsing the same - Google Patents

Abstract

PURPOSE: A dual band rod antenna and a transport device including the same are provided to easily control resonant frequency by including a small resonance adjust unit. CONSTITUTION: A resonance adjust unit (50) is electrically combined with one end of a first antenna conductor (10). The resonance adjust unit activates an antenna in different two bands. The resonance adjust unit is inserted into the inner side of a connection unit (40). The resonance adjust unit comprises a capacitor and an inductor.

Description

DUAL BAND ROD ANTENNA AND MOBILE DEVICE COMPRSING THE SAME}

The present invention relates to a dual band antenna, and more particularly, to an antenna capable of realizing a dual band without using a switch while increasing the gain.

Mobile devices such as cell phones, smart phones, personal digital assistants (PDAs), game consoles, and the like have various wireless signal transmission and / or reception functions. For example, the mobile device may transmit / receive WiFi signals, transmit / receive cellular signals, or receive mobile broadcast signals such as DMB. It is essential for the mobile device to include an antenna for transmitting and receiving wireless signals, the electrical length or shape of the antenna being determined according to the frequency of the wireless signal transmitting and receiving. In general, the electrical length of a monopole antenna is determined to be 1/4 of the wavelength of a transmitted / received signal, which is slightly shorter than 1/4 of the wavelength by bending an antenna conductor to add capacitance or inductance, or to add a separate element. It may be lost or lengthened. As such, since the length of the antenna is related to the wavelength of the transmitted / received signal, each antenna is required for each band in order to receive two or more different band signals. In addition, even when the antenna is configured to receive two or more signals having different wavelengths from one antenna, a separate configuration of the antenna should be added. For example, the prior art uses a switching circuit that connects one antenna to different matching circuits or signal processing circuits (eg, filters) according to the frequency of the transmitted and received signals. The use of multiple antennas or the use of switching circuits both increase manufacturing costs and hinder antenna miniaturization.

On the other hand, mobile broadcasts usually use signals in the UHF (Ultra High Frequency) or VHF (Very High Frequency) bands. Since the wavelengths of these band signals are tens of centimeters and several meters, respectively, the electrical length of an antenna for receiving these signals is measured. Is more than ten centimeters. However, mounting a dozen centimeter antennas on a mobile device will hinder the miniaturization of the mobile device and significantly deteriorate its appearance, so that a retractable or telescopic antenna that can be inserted / extracted (hereinafter referred to as Tractorable antennas ”are widely used.

As a method for miniaturizing a retractable antenna of ten centimeters or more, for example, a method of adding an inductance in series to the antenna as a matching circuit is employed. However, the gain of the antenna is known to be improved when the inductance is placed on the ground plane of the antenna to be out of the ground plane than to be matched in the terminal. For this purpose, the inductance is not formed with the ground plane. A configuration is used which is arranged so as to be arranged on the part, that is, exposed outside the terminal.

However, when the inductance is arranged to be exposed to the outside of the terminal, substantially the same effect as the feeding portion of the antenna is moved to the end of the inductor, it becomes difficult to connect the switching circuit to the antenna as in the prior art. In other words, since the position of the actual feeding portion of the antenna is outside the terminal, it is difficult to transmit and receive signals of several bands with one antenna through a switching circuit installed inside the terminal. If one antenna cannot be used for several bands, there is a problem that several antennas should be installed. Or, when using signals of different bands (for example, VHF and UHF bands) in different countries for the same service (for example, mobile broadcasting), the manufacturer of the mobile device must design and manufacture a separate device for each country. There is a problem of increased cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an antenna, particularly a retractable antenna, and a mobile device using the same that can be used in two or more bands even when the inductance is exposed to the outside.

According to a first aspect of the present invention for achieving the above object, an antenna comprising a first antenna conductor and a resonance adjustment unit electrically coupled to one end of the first antenna conductor, wherein the resonance adjustment unit is different from each other. There is provided a retractable antenna for operating in two bands.

The resonance adjusting unit may include a capacitor and an inductor connected in parallel.

The resonance adjusting part may be electrically inserted into the first antenna conductor and the other end of the resonance adjusting part may be inserted into the connection part connected to the feed part to electrically couple the first antenna to the connection part.

The resonance adjusting unit includes a first conductor and a second conductor exposed to the outside, a capacitor and an inductor connected between the first conductor and the second conductor, and the resonance adjusting unit is connected to the first antenna by the first conductor. It may be connected to a conductor, and the second conductor may be connected to a connecting portion to which the resonance adjusting portion is connected to the feeding portion.

In one embodiment, the two different bands are a Very High Frequency (VHF) band and an Ultra High Frequency (UHF) band.

The retractable antenna may be configured to be removable from a connector installed in the mobile device.

In one embodiment, the antenna is a second antenna conductor that can be inserted into the first antenna conductor, wherein one end of the first antenna conductor and the first antenna conductor are drawn when the second antenna conductor is withdrawn from the first antenna conductor. One end of the two antenna conductor is further electrically coupled to the second antenna conductor.

According to another aspect of the present invention, there is provided a mobile device provided with the retractable antenna.

The mobile device preferably does not include switching means for connecting the retractable antenna to different matching circuits.

According to the present invention, a dual band antenna can be easily implemented. In particular, when implementing a retractable antenna, it is possible to easily implement a dual band antenna while allowing insertion and withdrawal by inserting a small resonance adjustment unit. In addition, the resonance frequency of the antenna can be easily adjusted by adjusting the inductance and the capacitance.

1 shows the structure of a retractable antenna according to the prior art.
2 illustrates a structure of a dual band retractable antenna according to an embodiment of the present invention.
3 shows a structure of a resonance adjusting unit according to an embodiment of the present invention.
4 is a simulation result of a frequency response characteristic of a retractable antenna in which a matching is performed in a mobile apparatus according to the related art.
5 is a simulation result of a frequency response characteristic of a retractable antenna that is matched outside the mobile device according to the prior art.
6 is a simulation result of a frequency response characteristic of a dual band retractable antenna according to an embodiment of the present invention.
7 is a block diagram of a mobile device according to one embodiment of the invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be noted that the embodiments shown or described are exemplary and the invention is not limited to these embodiments.

As used herein, the term “electrical coupling” refers not only to the case where the two conductors are in direct contact with each other to allow the transfer of charge, but also to the arrangement in which the two conductors are not in direct contact with each other, but in such a way that current can be communicated through electromagnetic coupling. It includes what has become. Thus, even when two conductors are disposed with a dielectric interposed therebetween, the two conductors may be electrically coupled.

As used herein, the term “mobile device” is used to encompass all mobile devices, PDAs, smartphones, notebook computers, tablet PCs, and other mobile devices capable of transmitting or receiving wireless signals.

1 shows the structure of a retractable antenna according to the prior art. The retractable antenna of the prior art includes a first antenna conductor 100 and a second antenna conductor into which the first antenna conductor 120 can be inserted. The first antenna conductor 100 is configured in a cylindrical shape, and the second antenna conductor 120 is also configured in a cylindrical shape having a through hole having a diameter slightly larger than that of the first antenna conductor 100. Thus, the first antenna conductor 100 and the second antenna conductor 120 constitute a retractable antenna or a telescopic antenna that can be inserted and withdrawn. On the other hand, the inductor 140 is connected to the lower side of the second antenna conductor 120. The inductor 140 may be configured as a coil wound around the core 150. The inductor 140 is connected to the antenna conductor 120 by inserting the core 150 into the through hole of the second antenna conductor 120. . In addition, the core 150 is also inserted into the connection unit 160 so that the inductor 140 is connected to the connection unit 160. The connection unit 160 is connected to a power supply circuit inside the mobile device. As such, by coupling the inductor to the second antenna 120, the inductor 140 may be disposed outside the ground plane of the mobile device, and the gain of the antenna may be improved. However, a result is that power is substantially supplied to the antenna at the lower end of the inductor 140, that is, the connection position between the inductor 140 and the connection unit 160, and it is difficult or cumbersome to configure the antenna to operate in two or more bands. Installing a separate circuit inside the mobile device or in the connection unit 160 increases the manufacturing cost of the antenna, wastes the internal space of the mobile device or increases the volume of the connection unit 160. It is a deterrent to miniaturization.

2 illustrates a retractable antenna according to one embodiment of the present invention. The antenna may include a first antenna conductor 10 and a second antenna conductor 20, and the first antenna conductor 10 may be inserted into the second antenna conductor 20. To this end, the second antenna conductor 20 may be formed to have a circular cylindrical shape, the first antenna conductor 10 also has a circular outer circumference. However, if the hollow shape formed on the second antenna conductor 20 and the outer circumferential shape of the first antenna conductor 10 coincide, the outer circumference of the first antenna conductor 10 and the second antenna conductor 20 is not circular. It can be composed of other forms of. For example, the first antenna conductor 10 may be configured in the shape of a square pillar, and the second antenna conductor may be formed in a cylinder having a hollow in the shape of a square pillar.

In another embodiment, the first antenna conductor 10 is also hollow and additional antenna elements configured to be inserted into the first antenna conductor 10 may be included. That is, the number of antenna conductors configured in the telescopic form is not limited to two as shown. In another embodiment, it is also possible that the first antenna conductor 10 is not included in the antenna and the antenna is implemented as a rod antenna comprising only one antenna conductor 20. Even in the case of a retractable antenna having three or more antenna conductors or implemented as a rod antenna, the advantageous effects according to the features of the present invention described below can still be achieved.

In one example, the first antenna conductor 10 may have its distal end 12 bent outward to contact the inner surface of the second antenna sheath 20. As a result, the first antenna conductor 10 and the second antenna conductor 20 can be connected in series.

The resonance adjusting unit 50 is coupled to the lower side of the second antenna conductor 20. The resonance adjusting section 50 is also coupled to the connecting section 40, which is connected to a power supply circuit in the mobile device. As a result, the second antenna conductor 20 may be electrically coupled and fed to the connection portion 40 through a circuit formed in the resonance adjusting unit 50. In one embodiment, the resonance adjusting unit 50 is configured such that at least its upper end has a shape coinciding with the inner circumference of the second antenna conductor 20, and at least its lower end has a shape coinciding with the inner circumference of the connecting portion 40. As a result, the resonance adjusting unit 50 is inserted into and coupled to the second antenna conductor 20 and the connecting unit 40. In one embodiment, when the second antenna conductor 20 and the connecting portion 40 are coupled to the resonance adjusting portion 50, an insulator 30 is disposed between the second antenna conductor 20 and the connecting portion 40 so that You can cut off direct contact. When the second antenna conductor 20 and the connecting portion 40 are formed in a cylindrical shape, the insulator 30 may be formed in a ring shape and formed on an outer circumference of the resonance adjusting unit 50. Thus, when the resonance adjusting unit 50 is inserted into the second antenna conductor 20 and the connecting portion 40, the insulator 30 may be interposed between the antenna conductor 20 and the connecting portion 40 automatically.

The resonance adjusting unit 50 is a component that allows the antenna to operate in two different bands, and includes a circuit therefor, the detailed configuration of which will be described later.

The connection portion 40 may comprise a connector for connecting to the mobile device, which connector may be configured such that the connection portion 40 is detachable to the mobile device. Thus, the antenna can be separated from the mobile device and combined only in use. In another embodiment, the connector of the connection portion 40 may be coupled so as not to be removable from the power supply circuit of the mobile device. In addition, the connecting portion 40 may be configured to be rotatable about the piece 42. However, the present invention is not limited to the rotatable connecting portion 40 or the L-shaped connecting portion.

In one embodiment, the resonance adjuster may include a capacitor and an inductor connected in parallel. 3 illustrates a resonance adjusting unit according to an embodiment of the present invention. 3 (a) and 3 (b) show the front and rear surfaces of the resonance adjusting unit. As shown in FIG. 3A, a capacitor 54 is disposed in front of the resonance adjusting unit, and as shown in FIG. 3B, an inductor 56 is disposed in the rear of the resonance adjusting unit. The capacitor 54 and the inductor 56 may each be a discrete device such as a chip. The capacitor 54 and the inductor 56 may be formed on the substrate 52, which may be a printed circuit board (PCB) or a flexible printed circuit board (FPCB). In one embodiment, the capacitor and the inductor may be formed in a surface mount manner on the substrate.

In other embodiments, the capacitor 54 and inductor 56 may be installed on the same side of the substrate 52, different from that shown if the capacitor 54 and the inductor 56 make substantially parallel connections. Structures may also be included within the scope of the present invention.

The capacitor 54 and the inductor 56 are connected between the first conductor 58 and the second conductor 59, respectively, to form a parallel LC circuit. When the first conductor 58 and the second conductor 59 are exposed to the outside and the resonance adjusting unit 50 is inserted into the second antenna conductor 20 and the connecting portion 40, the second antenna conductor 20, respectively. It is connected to the inside of and the inside of the connecting portion 40. To this end, in one embodiment, both ends of the resonance adjusting unit 50 in which the first conductor 58 and the second conductor 59 are formed correspond to the inner circumference of the antenna conductor 20 and the connecting portion 40, for example. For example, it may be configured in a cylindrical shape. In another embodiment, the first conductor 58 and the second conductor 59 may be formed on both sides as well as the front and rear surfaces of the substrate 52 to make contact with the second antenna conductor 20 and the connecting portion 40. .

The principle of the operation of the resonance adjusting unit 50 will be described. In general, the impedance of the inductor is proportional to frequency, while the impedance of the capacitor is inversely proportional to frequency. Thus, at sufficiently high frequencies, the inductor operates in an open circuit with a very large impedance and the capacitor operates in a short circuit with a very low impedance, while at a sufficiently low frequency the inductor operates in a short circuit. And the capacitor operates as an open circuit. As a result, the antennas constitute different circuits at high and low frequencies, and function substantially as two antennas. The band in which the actual antenna operates can be determined by appropriately selecting the inductance of the inductor and the capacitance of the capacitor.

The values of inductance and capacitance are determined in consideration of the operating band of the antenna, the length of the antenna (length at the time of antenna drawing), and the like. For example, in one embodiment, if the antenna has a length of 120 to 180 mm and operates in the Very High Frequency (VHF) band and the Ultra High Frequency (UHF) band, the inductance is 100 nH and the capacitance is 2-3 pF. You can do

As a result, the dual band antenna can be easily implemented by simply introducing the resonance adjusting unit. In particular, when implementing a retractable antenna, there are many restrictions in changing the structure of the antenna conductor in order to enable the insertion and withdrawal of the antenna. A dual band can be easily inserted and drawn out by inserting a small resonance adjustment unit. An antenna can be implemented. In addition, the resonance frequency of the antenna can be easily adjusted by adjusting the inductance and the capacitance. In addition, since the resonance adjusting unit exists outside the ground plane of the mobile device, the gain improvement effect obtained by the antenna of FIG. 1 can be maintained as it is.

FIG. 4 shows the S-parameter simulation results of a typical retractable antenna (ie, the inductor is placed outside the ground plane and is matched inside the mobile device), and FIG. 5 shows that the inductor is grounded as shown in FIG. S-parameter simulation results of a retractable antenna placed out of plane (ie, matched outside the mobile device) are shown. The length of the antenna used in each simulation was 150 mm, and the inductance used in the simulation of FIG. 5 was 270 nH. As shown, it can be seen that the gain of the antenna of FIG. 5 is increased at a resonant frequency of about 0.25 GHz band. However, both antennas have only one resonant frequency and cannot operate as a dual band antenna.

6 shows an S-parameter simulation result of an antenna to which a resonance adjusting unit is added according to an embodiment of the present invention. The length of the antenna used in the simulation was 150 mm, the inductance was 150 nH, and the capacitance was 3 pF. As shown, it can be seen that in addition to the resonant frequency near 0.2 GHz an additional resonant frequency was formed near 0.55 GHz. Thus, unlike in Figures 4 and 5, it was confirmed that the antenna of the present invention can operate as a dual band antenna. Furthermore, it can be seen that the gain of the antenna is improved over that seen in FIG.

7 illustrates a mobile device according to one embodiment of the invention. Mobile device 80 may be a mobile phone, PDA, smart phone, notebook computer, tablet PC, or any other mobile device capable of transmitting or receiving wireless signals. In FIG. 7, the antenna 70 is coupled to the mobile device 80 and the mobile device 80 includes a space for accommodating the antenna so that the antenna 70 is inserted into the mobile device 80 when not in use. Can be accommodated. In use, it is exposed to the outside of the mobile device 80 and drawn out to extend its length. In other embodiments, however, the antenna connection 40 (FIG. 2) includes a connector configured to be detachable to the mobile device 80, so that it can be used to fit the mobile device 80 only in use. The mobile device can operate by receiving signals of two bands from the antenna 70 without including a separate switching circuit.

While specific embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications or changes can be made from the described embodiments without departing from the scope of the present invention. . Accordingly, the scope of the invention should be defined by the appended claims and equivalents thereof.

Claims (9)

A first antenna conductor; And
An antenna comprising a resonance adjusting unit electrically coupled to one end of the first antenna conductor,
The resonance adjusting unit allows the antenna to operate in two different bands.
antenna. The method of claim 1,
The resonance adjusting unit includes a capacitor and an inductor connected in parallel
antenna. The method of claim 1,
The resonance adjusting unit has one end inserted into the first antenna conductor and the other end inserted into a connection part connected to a feed part to electrically couple the first antenna and the connection part.
antenna. The method of claim 1,
The resonance adjusting unit,
First and second conductors exposed to the outside;
A capacitor and an inductor connected between the first conductor and the second conductor,
The resonance adjuster is connected to the first antenna conductor by the first conductor, and the resonance adjuster is connected to a connection portion connected to the feeder by the second conductor.
antenna. The method of claim 1,
The two different bands are the VHF (Very High Frequency) band and the UHF (Ultra High Frequency) band.
antenna. The method of claim 1,
The retractable antenna is configured to be removable from the connector installed in the mobile device
antenna. The method of claim 1,
A second antenna conductor that can be inserted into the first antenna conductor, wherein one end of the first antenna conductor and one end of the second antenna conductor are electrically connected when the second antenna conductor is withdrawn from the first antenna conductor. Combined with, further comprising the second antenna conductor
antenna. A mobile device provided with the retractable antenna according to any one of claims 1 to 5 or 7. The method of claim 8,
It does not include switching means for connecting said retractable antenna to different matching circuits.
Mobile device.

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