KR20040038558A - Mobile Phone Antenna Applicating Auto-tuning and Space Diversity - Google Patents

Abstract

PURPOSE: An antenna circuit of a cellular phone using auto tuning and space diversity is provided to optimize an antenna matching process by using an auto-tuning function for controlling automatically the antenna matching process. CONSTITUTION: An antenna circuit of a cellular phone using auto tuning and space diversity includes a duplexer(20), an RF switching unit(21), a first and a second auto tuning unit(22,24), and a first and a second antenna(26,27). The duplexer(20) is used for protecting a receiving unit, transmitting an RF signal, and supplying the received RF signal to the receiving unit. The RF switching unit(21) switches the RF signal to an optimum antenna according to a control signal. The first and the second auto tuning units(22,24) receive the RF signal and perform an antenna matching control process according to a transmitting/receiving sensitivity control signal. The first and the second antennas(26,27) transmit or receive the RF signal.

Description

Mobile Phone Antenna Applicating Auto-tuning and Space Diversity

The present invention relates to a mobile phone antenna to which autotuning and space diversity are applied.

In general, portable wireless terminals have an antenna device protruding in place outside the main body of a mobile phone for transmitting a signal to or receiving a signal from the other party. The trend of the wireless design of such a mobile phone is the miniaturization of the product. Accordingly, the antenna, which is one of the largest parts of the mobile phone, is designed to be as small as an antenna in consideration of reception strength and harmfulness of electromagnetic waves.

The external protruding antenna used in the mobile phone includes a monopole and a helical antenna, and FIG. 1 is a view for explaining the appearance of a mobile terminal external protruding antenna having a conventional monopole and helical antenna.

As shown in FIG. 1, the conventional externally protruding antenna protrudes when used in the mobile phone main body 10 and the upper edge of the mobile phone main body 10, and can be stored in the mobile phone main body 10 when not in use. A whip antenna portion 11 and a printed circuit board (PCB) 12 connected to the whip antenna portion 11.

Since the conventional mobile phone having an external projecting antenna is used by mounting the antenna on the outside of the phone, the antenna matching circuit is fixed to fixed values since the characteristics of the antenna are not severely affected by the position of the hand holding the mobile phone during a call. There was no problem in using it.

However, if you use Intenna (collectively referred to as the antenna mounted inside the mobile phone, intenna), the hand held by the user during the call often covers the intenna, which greatly affects the characteristics of the intenna (mobile phone According to the position of the hand to hold the fluctuation range of the radiation pattern and impedance of the antenna becomes very large), resulting in the degradation of the call, there was a problem that the call quality is degraded.

The present invention has been proposed to solve the above problems, by applying autotuning to automatically adjust the antenna matching, and by using a space diversity technique using two or more antennas, The purpose of the present invention is to provide a mobile phone antenna circuit using autotuning and space diversity to improve quality.

In addition, an object of the present invention is to provide a mobile phone antenna circuit to which the auto-tuning is applied to improve the call quality of the mobile phone by applying the auto-tuning to automatically adjust the antenna matching.

1 is a view for explaining the appearance of a mobile phone exterior protrusion antenna having a conventional monopole and helical antenna.

2 is a diagram illustrating an embodiment of a mobile phone antenna circuit to which autotuning and space diversity are applied according to the present invention;

3 is an exemplary configuration diagram of a general autotuning circuit used in the antenna circuit according to the present invention.

4A to 4D are explanatory views of the first to fourth embodiments showing the appearance of a cellular phone constructed using different antennas according to the present invention.

* Explanation of symbols for the main parts of the drawings

20: duplexer 21: RF switch

22, 24: autotuning circuit

23, 25: antenna basic L, C matching circuit

26, 27: antenna

According to an aspect of the present invention, there is provided a mobile phone antenna circuit including autotuning and space diversity, comprising: a duplexer for transmitting a radio frequency (RF) signal while protecting a receiver and supplying a received RF signal to the receiver; RF switching means for switching the transmitted RF signal to an optimal antenna according to the control of the control signal; First and second auto-tuning means for receiving the RF transmission and reception signal and adjusting antenna matching according to the transmission and reception RF signal environment according to the control of the transmission and reception sensitivity control signal; And first and second antennas for transmitting and receiving the RF signal.

In addition, the present invention provides a mobile phone antenna circuit to which autotuning is applied, comprising: a duplexer for transmitting a radio frequency (RF) signal while protecting a receiver and supplying a received RF signal to the receiver; Auto-tuning means for receiving the transmit / receive RF signal and adjusting antenna matching according to the transmit / receive RF signal environment according to the control of the transmit / receive sensitivity control signal; And an antenna for transmitting and receiving the RF signal.

In antenna design, a space diversity scheme is a method of obtaining two transmission antennas by separating two receiving antennas in space.

That is, since signals received from antennas spaced apart from each other undergo different phase shifts, they have low correlation characteristics with respect to each other. Here, having a low correlation means that multipath fading characteristics of one signal and the other signal are independent of each other.

Therefore, when one signal falls into deep fading, the other becomes less likely to fall into deep fading, and combining these two signals results in a signal with less multipath fading. In addition, since the mobile phone antenna has a directivity, transmission and reception can be performed in a specific direction, while NULL (transmission and reception) is not possible in a specific direction.

Therefore, by using two transmit / receive antennas having different directionalities, a different transmit / receive characteristic may be obtained by allowing another antenna to compensate for the transmit / receive characteristic of any one antenna in a bad direction.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating an embodiment of a mobile phone antenna circuit to which autotuning and space diversity are applied according to the present invention.

As shown in FIG. 2, a mobile phone antenna circuit employing auto-tuning and space diversity according to the present invention protects a receiver from an output RF signal and supplies a received RF signal to the receiver. A duplexer 20, an RF switch 21 for switching an transmitted RF signal to an optimal antenna, an autotuning circuit 22 for adjusting antenna matching to a change in a transmission / reception signal environment, and an optimum basic antenna Antenna base L, C matching circuits 23 and 25, and antennas 26 and 27 for RF signal emission and reception.

Antennas used in mobile phones include a Plain Inverse F-Type Antenna (PIFA), an antenna formed by patterning a mobile phone backhousing, a dielectric helical antenna, and the like. One of these antennas, or two antennas of different types, was used.

Here, the helical antenna is a kind of microwave antenna, and is an antenna made by winding a metal wire in the shape of a screw. When the length of the screw wire is wound about a wavelength, a directional circular polarized wave propagated in the axial direction of the screw is radiated. If the winding length is much smaller than the wavelength, it is radiated at right angles, and high gain is obtained over a fairly wide frequency range.

PIFA (Plane Inverted F Antenna) is a planar design of an inverted F antenna, and is a type of antenna that feeds at the center of the inverted L antenna. In other words, the reverse F type antenna is fed on the way to improve the matching of the reverse L type antenna.

The control signals 201 and 202, which are input to control the auto tuning circuits 22 and 24, are pulse width modulation (PWM) provided from the mobile station modem (MSM) of the cellular phone. This is the signal to be controlled.

3 is an exemplary configuration diagram of a general autotuning circuit used in the antenna circuit according to the present invention.

As shown in FIG. 3, the general autotuning circuit inputs control signals PWM 201 and 202 provided from the MSM of the terminal so that the capacitance C of the varactor diode 34 can be changed. A low pass filter 30 for converting the input control signals 201 and 202 into a DC voltage signal, and a variable capacitance diode whose capacitance C changes in accordance with the voltage of the signal output from the low pass filter 30. A varactor diode 34, two resistors 31 and 35 used as biases of the varactor diode 34, and two for blocking a DC voltage signal from a transmission / reception signal input to an autotuning circuit section. Two capacitors (32, 33).

Here, the C values of the L and C basic matching circuits are varied according to the capacitance C value which is changed in the varistor diode 34. That is, since the L values of the L and C basic matching circuits are fixed, the transmission / reception sensitivity of the antenna is determined by the value of the capacitance C of the varactor diode 34 that varies according to the control signal.

4A to 4D are explanatory views of the first to fourth embodiments showing the appearance of a mobile phone constructed using different antennas according to the present invention.

4A illustrates a case of using two helical antennas according to an embodiment of the present invention.

4B illustrates a case of using one PIFA type antenna and one back housing antenna attached to a back housing of a mobile phone as a second embodiment according to the present invention.

4C illustrates a case of using one PIFA type antenna and one helical antenna as a third embodiment according to the present invention.

4D illustrates a case of using a helical antenna and a back housing antenna formed by attaching a pattern to a back housing of a mobile phone as a fourth embodiment according to the present invention.

Up to now, the embodiment of using two antennas has been described. However, the antenna circuit of the present invention can be applied to the same case of using one antenna. In this case, the switching circuit is removed and two Only one of the autotuning circuit and the two antenna L and C basic matching circuits needs to be applied.

In addition, if the size of the antenna becomes smaller and the price becomes cheaper, it is possible to use two or more antennas, and according to the addition of the antenna, the circuits (autotuning circuit, antenna L, C basic matching circuit, etc.) The addition of H can result in a more efficient space diversity scheme than using two antennas.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention as described above, by using a mobile phone antenna designer, intenna to apply the autotuning function that automatically adjusts the matching of the antenna to match the best match in the position of the hand holding the phone or the weak electric field, etc. By applying space diversity using two or more antennas at the same time, not only are they less affected by the hand holding the mobile phone when using the mobile phone, but also the call quality can be improved in the weak electric field.

Claims (9)

In the mobile phone antenna circuit applying auto tuning and space diversity, A duplexer for transmitting a radio frequency (RF) signal while protecting a receiver and supplying a received RF signal to the receiver; RF switching means for switching the transmitted RF signal to an optimal antenna according to the control of the control signal; First and second auto-tuning means for receiving the RF transmission and reception signal and adjusting antenna matching according to the transmission and reception RF signal environment according to the control of the transmission and reception sensitivity control signal; And First and second antennas for transmitting and receiving the RF signal Cell phone antenna circuit applying auto-tuning and space diversity comprising a. In the mobile phone antenna circuit to which the auto tuning is applied, A duplexer for transmitting a radio frequency (RF) signal while protecting a receiver and supplying a received RF signal to the receiver; Auto-tuning means for receiving the transmit / receive RF signal and adjusting antenna matching according to the transmit / receive RF signal environment according to the control of the transmit / receive sensitivity control signal; And Antenna for transmitting and receiving the RF signal Cell phone antenna circuit to which the autotuning is applied. The method according to claim 1 or 2, An antenna basic L (Inductor) -C (Condenser) matching means located between the auto tuning means and the antenna and configured to be adjusted to an optimal antenna matching value according to the auto tuning means Cell phone antenna circuit to which the auto-tuning and space diversity further comprising. The method according to claim 1 or 2, The transmission and reception sensitivity control signal, Cell phone antenna circuit applying auto-tuning and space diversity, characterized in that the PWM (Pulse Width Modulation) signal provided from the mobile station modem (MSM) of the terminal. The method of claim 1, The mobile phone antenna circuit to which the auto-tuning and space diversity is applied, Cell phone antenna circuit using auto tuning and space diversity, characterized by using two helical antennas. The method of claim 1, The mobile phone antenna circuit to which the auto-tuning and space diversity is applied. Cell phone antenna circuit using auto tuning and space diversity, characterized by using one PIFA (Plain Inverse F-Type Antenna) antenna and one backhousing antenna. The method of claim 1, The mobile phone antenna circuit to which the auto-tuning and space diversity is applied, Cell phone antenna circuit using auto tuning and space diversity, characterized by using one PIFA type antenna and one helical antenna. The method of claim 1, The mobile phone antenna circuit to which the auto-tuning and space diversity is applied, Cell phone antenna circuit with auto tuning and space diversity characterized by using one helical antenna and one back housing antenna. The method of claim 1, The mobile phone antenna circuit to which the auto-tuning and space diversity is applied, Cell phone antenna circuit using auto-tuning and space diversity, characterized by using three or more different types of antennas.