WO2012105773A2

WO2012105773A2 - Multimode high-frequency module

Info

Publication number: WO2012105773A2
Application number: PCT/KR2012/000679
Authority: WO
Inventors: 남창기
Original assignee: Nam Chang Gi
Priority date: 2011-01-31
Filing date: 2012-01-30
Publication date: 2012-08-09
Also published as: KR101107650B1; WO2012105772A3; JP2014509484A; WO2012105772A2; JP5817024B2; WO2012105773A3

Abstract

The present invention relates to a multimode high-frequency antenna module having high isolation between antennas in a wireless communication device having at least two antennas operating in multiple modes. The antenna module includes a multimode antenna which resonates in at least one frequency band. A power feeder module comprises a feeder unit and two or more strip lines electrically mutually parallel. The feeder unit supplies power to be radiated through the multimode antenna. The two or more strip lines deliver the power supplied from the feeder unit to the multimode antenna. As many feeder points, for connecting the power supplied through said at least two strip lines to the multimode antenna, as there are strip lines are formed. The multimode high-frequency antenna module further comprises a printed circuit board on which an electrical circuit of the power feeder module is formed.

Description

Multimode High Frequency Module

The present invention relates to an antenna of a wireless communication device, and more particularly, to a high frequency module of a wireless communication device for reducing coupling between antennas in a multimode antenna to have high isolation characteristics.

Background Art In recent years, services for providing various information transfer and information providing services through wireless have been in full swing, and many wireless communication devices have been developed and provided for practical use. These services are diversified year by year, such as telephones, televisions, and local area networks (LANs). In order to use all the services, users must possess radio communication devices corresponding to individual services.

In order to improve convenience of a user using such a service, a multi-mode wireless communication device capable of using a plurality of services with one wireless communication device instead of a separate wireless communication device according to each service has been partially realized.

In general, the service of information transmission by radio uses electromagnetic waves as a medium, so that a plurality of services are provided to the user by using one frequency for one type of service in the same service area. Therefore, the wireless communication device must have a function of transmitting and receiving electromagnetic waves of a plurality of frequencies.

In the conventional radio communication apparatus, for example, a method of preparing a plurality of single mode antennas corresponding to one frequency and mounting them in one radio communication apparatus has been adopted.

In this method, in order to operate each single-mode antenna independently, it is necessary to mount them at a distance of a wavelength, and the frequency of electromagnetic waves used for services related to normal information transmission is hundreds of times due to the limitation of free space propagation characteristics. Since the distance from the antenna is several tens of centimeters to several meters because it is limited to MHz to several kilohertz, it is difficult to carry the user due to the size of the terminal, and the antennas having sensitivity at different frequencies are arranged at a distance. Therefore, a high frequency circuit coupled to the antenna also needs to be separated and provided for each frequency.

For this reason, it is difficult to apply the integrated circuit technology of the semiconductor, and the problem of not only increasing the dimensions of the wireless communication device but also causing the high cost of the high frequency circuit. Even if the integrated circuit technology is forcibly integrated, the necessity of combining the high-frequency cable from the high-frequency circuit to the antennas separated by individual distances is generated.

By the way, since the shaft diameter of the high frequency cable applicable to the radio communication apparatus of a user portable dimension has a diameter of about 1 millimeter, the transmission loss of this high frequency cable reaches several s / m. The use of such high-frequency cables increases the power consumed by the high-frequency circuits, thereby significantly reducing the use time of the wireless communication device or increasing the size of the battery, making it difficult for a user to carry the wireless communication device.

As an example, antennas capable of operating at different frequencies even in a wireless communication apparatus using a two-frequency common antenna have been proposed in Japanese Patent Laid-Open Nos. 61-295905 and 1- 1805805. However, in such a structure, since a transmitter and a receiver are required for each of the input and output terminals at different locations, there is a problem in that integration required for a small device such as a wireless communication device is difficult.

In order to solve this problem, Korean Patent No. 10-0774071 discloses a small multimode antenna capable of sharing one feed point at a plurality of frequencies and a high frequency module using the antenna, and one end of a radiation conductor. A single feed point common in frequency is used, and a first port resonant circuit is connected to one end thereof and a second first port resonant circuit is connected to the other end of the radiating conductor. It is proposed that the conductance component of the admittance when the free space is seen from the feed point is the same as the characteristic admittance of the high frequency circuit, and the susceptance component of the admittance is canceled at a plurality of frequencies by a resonance circuit connected to the feed point. It became.

1 is a schematic structural diagram of a small multi-mode antenna according to Korean Patent Registration No. 10-0774071.

As another example, Korean Patent Laid-Open Publication No. 1998-702904 uses an antenna and a diplexer operating at a first frequency and a second frequency that is the lowest frequency far from the first frequency, but the diplexer is a capacitive element and an inductive A dual frequency antenna is disclosed that includes an element and combines two signals so that a single coaxial cable can be used for the antenna and provides impedance matching at the first and second operating frequencies.

2 is a schematic structural diagram of a dual frequency antenna according to Korean Patent Laid-Open Publication No. 1998-702904.

As another example, Korean Patent Laid-Open Publication No. 10-2010-0026653 includes a ground plane having a finite plane and made of a conductor for use in a multiband by operating an antenna as a monopole or PIFA antenna using a wireless switch; An antenna body for transmitting and receiving radio waves; A feed line electrically interconnecting the ground plane and the antenna body; A shorting pin for grounding the antenna body to the ground plane; And a switch connected to the shorting pin and controlling a connection state with a ground plane of the antenna body.

3 is a schematic structural diagram of a planar inverted F antenna according to Korean Patent Laid-Open No. 10-2010-0026653.

Although the prior art provides an antenna for operating a multi-band or multi-mode in a small wireless communication device, a solution to the problem that the radio performance is reduced by coupling between antennas as a plurality of antennas are provided. Not present

The present invention has been proposed to solve the above problems, and to provide a high frequency module having high isolation characteristics. Specifically, in the multi-mode high-frequency module of the wireless communication device including the antenna module and the power feeding module, each antenna is connected in parallel and independently fed to have high isolation characteristics, and when operating in a multi-band, tuning by operating frequency may be possible. In addition, it is to provide a multi-mode high-frequency module of a wireless communication device having a high isolation characteristic that can be made small by reducing the electrical length of the feed line.

High frequency module including an antenna module and a power supply module according to the present invention for achieving the above object,

The antenna module includes a multimode antenna resonating in at least one frequency band,

The feed module includes at least two strip lines that are at least electrically parallel to the feed portion, wherein the feed portion supplies power radiated through the multimode antenna, and the at least two strip lines are supplied from the feed portion. Delivers power to the multimode antenna,

A printed circuit board further comprising a feeding point for connecting the power supplied through the at least two strip lines to the multimode antenna, the number of the at least two strip lines being formed, and wherein the feeding module is formed of an electrical circuit;

The antenna module combines the multi-mode antenna coupled to the power supply module in the opposite direction with respect to the printed circuit board, and supports the multi-mode antenna and couples the multi-mode antenna to the antenna support. Further comprising a portion and the antenna coupling portion may be formed on one side of the antenna support,

The other side of the antenna support is further formed with a fastening portion for fastening the antenna support to the printed circuit board,

The printed circuit board may further include a coupling groove coupled to the coupling portion at a position opposite to the coupling portion formed on the antenna support portion.

The power supply module,

A short line is further formed between the feed portion and the ends of the at least two strip lines electrically connected to each other connected to the feed point to supply the in-phase power to the antennas respectively connected to the at least two strip lines. ,

At least two or more tuning lines are provided between the short line and ends of at least two strip lines connected to the feed point to adjust the resonant frequency of the multimode high frequency module and to attenuate coupling between the multimode antennas. Characterized in that each is further formed between the strip line,

And said tuning line is equivalently a series coupling of capacitor, capacitor and inductor or parallel coupling of capacitor and inductor.

On the other hand, the short line connected between the at least two strip line is characterized in that the length of 1/4 wavelength of the desired resonance frequency.

The multi-mode high-frequency module of the wireless communication device including the antenna module and the power feeding module according to the present invention having the above configuration has a high isolation characteristic by independently feeding each antenna connected in parallel and operating in a multi-band mode. In this case, not only the tuning by operating frequency is possible but also the high isolation characteristic, which makes it possible to manufacture small by reducing the electrical length of the feed line.

4 is a schematic structural diagram of a multi-mode high frequency module of a wireless communication device according to the present invention.

5 is a view for explaining the principle that the coupling between the antenna is attenuated in the multi-mode high-frequency module of the wireless communication device according to the present invention.

FIG. 6 is a diagram of FIG. 5 converted to an equivalent circuit.

7 illustrates isolation characteristics between antennas at an operating frequency in a wireless communication device equipped with a multi-mode antenna according to the present invention.

8 is another example of a structure in which an antenna is mounted on a PCB substrate in a wireless communication device equipped with a multi-mode antenna according to the present invention.

9 illustrates standing wave ratios and frequency response characteristics when an equivalent capacitor value of a tuning line is 1.2 pF in a wireless communication device equipped with a multi-mode antenna according to the present invention.

10 is a standing wave ratio and frequency response characteristics when an equivalent capacitor value of a tuning line is 1.5 pF in a wireless communication device equipped with a multi-mode antenna according to the present invention.

FIG. 11 is a standing wave ratio and frequency response characteristic when an equivalent capacitor value of a tuning line is 2.2 pF in a wireless communication device equipped with a multi-mode antenna according to the present invention.

12 illustrates standing wave ratios and frequency response characteristics when an equivalent capacitor value of a tuning line is 3 pF in a wireless communication device equipped with a multi-mode antenna according to the present invention.

FIG. 13 illustrates standing wave ratios and frequency response characteristics when an equivalent capacitor value of a tuning line is 5pF in a wireless communication device equipped with a multi-mode antenna according to the present invention.

[Description of the code]

410: antenna module 411, 412: antenna

420: printed circuit board 430: power supply module

431: first strip line 432: second strip line

441: tuning line 460: short line

511, 512: antenna

521, 522: feed point 531, 532: strip line

541, 542: equivalent capacitor 551, 552: equivalent inductor

560: short line

611 and 612

strip lines

621 and 622 equivalent capacitor

631, 632: equivalent inductor 650: impedance matching circuit

810: antenna support 820: antenna

821: antenna coupling portion 822: coupling portion

830: printed circuit board 831: fastening groove

840: feed point 850: strip line

860: tuning line 8621: equivalent capacitor

862: equivalent inductor 870: short line

880: power supply

4 is a schematic configuration diagram of a multi-mode high frequency module of a wireless communication device according to the present invention, which simplifies a structure in which a high frequency module having the multi-mode antenna of FIG. 8 is mounted on a printed circuit board.

The high frequency module according to the present invention includes a printed circuit board 420, a power feeding module 430 mounted on the printed circuit board 420, and an antenna module 410 fastened to the printed circuit board.

In the power supply module 430,

strip lines

431 and 432 for transmitting power input from the power supply to the

antennas

411 and 412 are electrically formed in parallel with each other, and the start of the

strip lines

431 and 432 is performed. A short line 460 is formed at one side of the

strip lines

431 and 432 between the portions P1 and P2 and the

antennas

411 and 412, and the short line 460 and the

antennas

411 and 412. In addition to the strip line (431, 432) between the tuning line 441 is provided. The tuning line 441 consists of an inductor and a capacitor to provide high isolation between ports.

The antenna module 410 is provided with

antennas

411 and 412 that are multi-mode, that is, resonate in at least one or more frequency bands to radiate power.

FIG. 5 is a circuit diagram of FIG. 4, wherein a power supply is connected to P1 and P2, and

strip lines

531 and 532 are connected to P1 and P2, respectively, and a short is formed at one side of the

strip lines

531 and 532. Lines 560 are connected, and feed ends P3 521 and P4 522 are electrically connected to

antennas

511 and 512 at ends of the

strip lines

531 and 532, and the feed points P3 521. Power is supplied to the

antennas

511 and 512 through the P4 522. Tuning line consisting of

inductors

551 and 552 and

capacitors

541 and 542 in

strip lines

531 and 532 between the feed points P3 521 and P4 522 and the short line 560 (not shown). ) More included.

FIG. 6 shows the power supply module converted to an equivalent circuit in FIG. 5.

The power supply module of FIG. 5 may be simplified to a two-port network, and the tuning line 441 of FIG. 4 may be equivalent to the

capacitors

621 and 622 and the

inductors

631 and 632.

In the configuration described above, the port P3 and the port P4 have a phase difference of 90 degrees electrically, and the port P2 has a 180 degree phase difference electrically with respect to the port P1, and the same magnitude of current is applied, thereby providing high isolation characteristics.

Generally, since port 2 and port 1 preferably have high isolation characteristics, various techniques have been developed for this purpose. However, as shown in FIG. 4, the strip line 431 and the strip line 432 are referred to as λ / 4 (λ). : The design method to have the electrical length of (wavelength of the resonant frequency) is dominant, but it is not easy to design to have an electrical length of λ / 4 on the printed circuit board (PCB), the present invention is equivalent In addition, a structure is proposed in which the ports P1 and P2 have an electrical length of λ / 4 even though the electrical length is shortened by adding the tuning lines L2 represented by the

inductors

631 and 632 and the

capacitors

621 and 622. .

Hereinafter, the principle of coupling attenuation between antennas of the multi-mode high frequency module according to the present invention will be described with reference to FIGS. 7 and 9 to 13.

As is known, the standing wave ratio is a ratio of the minimum value and the maximum value of the standing wave formed by the incident power and the reflected power, and the closer to 1, the smaller the amount of reflection and the better the impedance matching.

9 (a) to 13 (a) show the standing wave ratios measured by simulation according to the frequency while changing the value of the capacitor.

On the other hand, the coupling between one terminal and the other terminal is preferably minimized, so the power is measured on the other terminal while power is supplied to one side, and the isolation between the terminals is measured as power.

9 (b) to 13 (b) show the measurement of power at a terminal to which power is not supplied by simulation according to frequency.

Table 1 below summarizes these measured values. As shown in Table 1, it can be seen that the standing wave ratio has the lowest value (1.14) in the resonant frequency band at 3pF, and 1.17 at 2.2pF and 3pF at It can be seen that it has a similar performance to.

On the other hand, the isolation characteristic between the terminals, that is, the isolation value is the lowest value in the resonant frequency region at 2.2pF (-30.6dB), which is about 12dB than -18.4dB at 3pF, which is 16 times different. That is, it can be seen that the isolation characteristic is improved by 16 times compared to 3.0 pF at 2.2 pF. Accordingly, it can be seen that it is preferable to select 2.2 pF as the value of the equivalent capacitor of the tuning line.

Table 1

	1.2pF (standing wave ratio / isolation degree)	1.5pF (standing wave ratio / isolation degree)	2.2pF (standing wave ratio / isolation chart)	3pF (standing wave ratio / isolation degree)	5pF (standing wave ratio / isolation chart)
One	1.31 / -4.2dB	3.39 / -7.4dB	2.70 / -5.8dB	2.96 / -6.9 dB	1.78 / -11.8 dB
2	3.25 / -5.8dB	1.92 / -10.1 dB	1.19 / -9.1dB	1.19 / -11.9dB	1.36 / -29.9dB
3	3.00 / -8.1dB	1.70 / -17.0dB	1.18 / -30.6dB	1.14 / -18.4dB	1.47 / -11.4 dB
4	2.75 / -12.9 dB	1.51 / -23.4dB	1.22 / -12.7 dB	1.16 / -10.7dB	1.55 / -8.6dB
5	1.57 / -13.2dB	2.04 / -11.1dB	2.07 / -8.9dB	1.79 / -8.5dB	2.13 / -7.8dB

Referring to FIG. 6, the current applied through the port P1 is met at the port P2 through the loop L1 passing through the short line 640 and the loop L2 passing through the tuning line, and the currents passing through each loop have the same magnitude but phase 180 degrees from each other. It is reversed and canceled out.

Eventually, the amount of power applied from port P1 to port P2 becomes substantially zero, so that port P2 has high isolation characteristics to port P1, and the power applied to port P2 also goes through loop L1 and loop L2 at port P1. The power is of the same magnitude and antiphase to cancel each other out so that port P1 also has high isolation for port P2.

On the other hand, the power applied to the port P3 and the port P4, that is, the magnitude of the current is preferably the same, for this purpose it can be achieved by appropriately adjusting the values of the inductor and the capacitor of the tuning line.

As described above, in order to maintain the electrical length between the strip lines at λ / 4, the PCB substrate requires a space that allows sufficient electrical length. Although not possible in the present invention, this problem can be achieved by adjusting the length and width of the tuning line equivalent to the inductor and the capacitor. Meanwhile, the inductor and the capacitor may be set to appropriate values to match the phase and impedance of the power radiated to the antenna. You can also choose.

Meanwhile, a separate impedance matching circuit 650 may be further added to the input ports P1 and P2 for impedance matching with the antenna.

In FIG. 7, a line marked with '□' is a measure of isolation between antennas, that is, attenuation of coupling, and a line marked with 'Δ' measures return loss from an antenna.

As shown in FIG. 7, it can be seen that the isolation between antennas is rapidly increased near the resonance frequency of about 2.5 GHz, and the antenna return loss is significantly reduced.

That is, the multi-mode high-frequency module according to the present invention can be seen that the coupling between the antenna is significantly attenuated near the desired resonant frequency to reduce the return loss in the antenna, thereby improving the radiation performance.

Meanwhile, in FIG. 4 to FIG. 6, the isolation characteristic may be varied by changing the value of the capacitor in the tuning line formed between the strip lines by changing the transfer characteristic according to the capacitor.

Specifically, if the capacitor value is increased, the band having excellent isolation characteristics, i.e., coupling attenuation, is moved to the low frequency band, and if the capacitor value is decreased, the isolation characteristic is moved to the high frequency band, so that the desired resonance frequency is varied. By varying the value of the capacitor, the coupling of the antenna can be significantly reduced at the desired resonant frequency.

8 is another example of a structure in which a high frequency module with a multi-mode antenna according to the present invention is mounted on a printed circuit board.

As shown in FIG. 8, the multi-mode high frequency module according to the present invention basically includes an antenna module, a power supply module, and a printed circuit board.

The antenna module includes a multi-mode antenna 820 resonating at a plurality of frequencies and an antenna support 810 that supports the antenna and is coupled to a printed circuit board. The antenna support 810 includes an antenna 820. The antenna coupling part 821 is formed on one side to be firmly coupled to the antenna support 810, and the antenna support 810 is fastened to fasten the antenna support 810 to the printed circuit board 830. The part 822 is formed in the other side.

A fastening groove 831 is formed in the printed circuit board 830 to fasten the antenna support 810 so that the fastening portion 822 is coupled to the fastening groove 831 so that the antenna support 810 is a printed circuit. It is fixed to the substrate 830.

According to the above configuration, when the antenna module is damaged or damaged while using the high frequency module, when the fastening part 822 is separated from the fastening groove 831, the antenna module and the printed circuit board can be separated, so that the entire high frequency module is removed. It is possible to replace only the failed module without having to replace it, which increases the reusability of the high frequency module.

In addition, the printed circuit board 830 is provided with a feed point 840, that is, a connection pad for transmitting power supplied from the power supply 880 to the antenna module.

The power supply module includes a power supply 880, a strip line 850, a tuning line 860, and a short line 870.

The tuning line includes an equivalent capacitor 861 and an equivalent inductor 862.

Since functions for each component have been described with reference to FIG. 4, detailed descriptions thereof will be omitted.

Claims

In the multi-mode high frequency module including the antenna module 410 and the power supply module 430,

The antenna module 410 includes multimode antennas 411 and 412 that resonate in at least two frequency bands.

The power supply module 430 is

Two or more strip lines 431 and 431 that are electrically parallel to each other to transfer the power supplied from the power supply P1 and P2 to the multimode antennas 411 and 412;

Between the two or more strip lines 431, 432 are added to the strip lines 431, 432 and equivalently formed by the combination of capacitors 541, 542 or capacitors 541, 541 and inductors 551, 552. And a tuning line 441.
In the multi-mode high frequency module including the antenna module 410 and the power supply module 430,

The antenna module 410 includes multimode antennas 411 and 412 that resonate in at least two frequency bands.

The power supply module 430 is

Two or more strip lines 431 and 431 that are electrically parallel to each other to transfer the power supplied from the power supply P1 and P2 to the multimode antennas 411 and 412;

The multimode high frequency module is connected between the two or more strip lines 431 and 432 to connect a short line 460 for supplying antiphase power to an antenna connected to the two or more strip lines 431 and 432, respectively. .
The method of claim 2,

And the short line connected between the two or more strip lines (431, 432) has an electrical length of 1/4 wavelength of a desired resonance frequency.
The method of claim 1,

The resonant frequency of the multimode high frequency module is varied by changing the value of the capacitor (541, 542), thereby attenuating the coupling between the multimode antennas (411, 412).
The method of claim 1,

The value of the capacitor (541, 542) or inductor (551, 552) constituting the tuning line (441) is adjusted to the length and width of the tuning line (441).
The method of claim 1,

The combination of the equivalent capacitor and inductor of the tuning line 441 is in series or in parallel.
The method according to claim 1 or 2,

The multi-mode high frequency module, characterized in that it further comprises a printed circuit board 420, the electrical circuit of the power supply module (430) is formed.
The method according to claim 1 or 2,

The feeding point (P3, P4), which is a connection pad for connecting the power supplied from the two or more strip lines (431, 432) to the multi-mode antenna is characterized in that formed by the number of the at least two stream lines (431, 432) Multimode high frequency module.
The method according to claim 1 or 2,

The antenna module 410 has an antenna support 810 for supporting the multi-mode antenna 820 and coupled to the printed circuit board 830,

The antenna support 810 further includes an antenna coupling part 821 for coupling the multimode antenna 820, and the antenna coupling part 821 is formed at one side of the antenna support 810. Multimode high frequency module.
The method of claim 9,

The other side of the antenna support 810, the multi-mode high-frequency module, characterized in that the fastening portion 821 is further formed to fasten the antenna support (810) to the printed circuit board (830).
The method of claim 10,

The printed circuit board 830 further includes a fastening groove 831 coupled to the fastening part 821 at a position opposite to the fastening part 821 formed on the antenna support 810. Multimode high frequency module.