KR101698879B1 - Antenna and method for operating an antenna - Google Patents

Abstract

The antenna includes a first antenna element A1, a first feed tap F1 for supplying a first frequency to the first antenna element A1, a second feed tap F1 for supplying a second frequency to the first antenna element A1, A first shorting tab S1 arranged between the first supply tab F1 and the second supply tab F2 and short-circuiting the first antenna element A1 to the ground potential GND, And a tuning slot T arranged between the first shorting tab S1 and the second feeding tab F2. A plurality of switches SW1, SW2, SW3 are provided so that the guiding operation of the tuning slot T can be changed.

Description

METHOD FOR OPERATING AN ANTENNA AND AN ANTENNA < RTI ID = 0.0 >

The present invention relates to antennas for mobile telephones (or cellular telephones) and similar radio devices. These antennas must be compact and handle multiple frequency bands. Examples of radio frequency bands are 824 to 960 MHz, 1710 to 2170 MHz and 2300 to 2700 MHz.

It is an object of the present invention to provide a method of operating an antenna and an antenna, the antenna having a small size and handling the above-mentioned frequency band.

The present invention relates to an antenna device comprising a first antenna element, a first supply tab for supplying a first frequency to the first antenna element, a second supply tab for supplying a second frequency to the first antenna element, A first shorting tab arranged between the taps and shorting the first antenna element to a ground potential and a tuning slot arranged between the first shorting tab and the second feeding tab. A plurality of switches may be provided to vary the inductive behavior of the tuning slots. According to the induction operation of the tuning slot, the first antenna element resonates at either the first frequency or the second frequency. Thus, without requiring an additional antenna to increase the size of the antenna, the first antenna element can operate in two frequency bands.

In one embodiment, the plurality of switches comprises: a first switch having a first connection point coupled to a first supply tap and a first frequency supply and a second connection point coupled to a ground potential; A second switch having a first connection point coupled to a second frequency source and a second connection point coupled to a second supply tab; And a third switch having a first connection point coupled to a second frequency supply and a second connection point coupled to a ground potential. The switch is used to change the inductive operation of the tuning slot and to short-circuit and connect the frequency source.

In one embodiment, the second switch is coupled to the second supply tab by a matching capacitance. The matching capacitance is used to increase the resonant frequency of the first antenna.

In one embodiment, at least the second of the plurality of switches is a capacitive RF micro-electromechanical system (MEMS) switch. Capacitive RF MEMS switches are easier to implement than galvanic RF MEMS switches.

In one embodiment, the matching capacitance is at least partially provided by the capacitance of the capacitive RF EMES switch used as the second switch. Thus, by using the capacitance of the MEMS switch, the size of the matching capacitance can be reduced, or the separate matching capacitance is completely eliminated.

In one embodiment, the antenna further comprises a second antenna element corresponding to the first antenna element, and the second antenna element A2 comprises a printed circuit board (PCB) on which the first antenna element A1 is arranged, ) On the opposite side of the side surface.

If the antennas are operating at the same time, the arrangement of the first and second antenna elements on the opposite side induces a reduction in electromagnetic interference between the antennas. Moreover, if the antenna is as far away as possible, the diversity of the signal path to the antenna is increased.

In one embodiment, the antenna further comprises a third antenna element, wherein the third antenna element comprises a third supply tab supplying a third frequency to the third antenna element and a third supply tab supplying a third frequency to the third antenna element, Tab. The third antenna element may be used to receive and radiate electromagnetic wave energy at a frequency that the first antenna element can not efficiently convert.

In one embodiment, the first frequency is 1700 to 2170 MHz, the second frequency is 2300 to 2700 MHz, and the third frequency is 824 to 960 MHz. These frequencies are commonly used to operate in GSM, CDMA, UMTS, WiMAX and WiFi systems.

The present invention further provides a method for operating the above-described antenna. The first antenna element is selected to emit and receive electromagnetic energy at either the first frequency or the second frequency by changing the inductive operation of the tuning slot. The inductive operation of the tuning slot is determined by whether the first antenna element resonates at a first frequency or at a second frequency.

In one embodiment, the first antenna element is configured such that the tuning slot is configured to operate with a series inductance when operating at a first frequency, and the tuning slot is configured to operate with a parallel inductance when operating at a second frequency. The first antenna element is composed of a plurality of switches.

In one embodiment, when operating at a first frequency, the first switch and the second switch are open and the third switch is closed, and when operating at a second frequency, the first switch and the second switch are closed and the third switch is open. To prevent the first antenna element from being excited at each frequency, the first switch and the third switch short-circuit the first frequency source and the second frequency source, respectively. The second switch is used to isolate the second frequency source. The switch also changes the impedance conversion due to supply and shorting taps.

In one embodiment, the capacitance of the second switch is selected such that the first antenna element resonates at the second frequency. The capacitance of the second switch is used as the matching capacitance.

In one embodiment, when operating at a first frequency, the impedance at the first supply tap is matched to the impedance of the first frequency source by adjusting the relative width of the first supply tab to the width of the first shorting tab, Frequency, the impedance at the second supply tap is matched to the impedance of the second frequency source by adjusting the relative width of the second supply tab to the combined width of the first shorting tab and the first supply tab. This allows impedance conversion due to supply and shorting taps that are independent of each other at the first frequency and the second frequency.

In one embodiment, the first antenna element and the second antenna element operate in a multiple input / multiple output (MIMO) or diversity manner. Simultaneous use of the first antenna element and the second antenna element is used to improve communication performance.

In one embodiment, when operating at a third frequency, the first switch and the third switch are closed and the second switch is open. This arrangement of switches induces better isolation of the first antenna element and the third antenna element.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described using the detailed description of the invention and the accompanying drawings.
1 shows an embodiment of an antenna having a first antenna element and a third antenna element.
2 shows a configuration of a switch for operating a first antenna element at a first frequency.
Fig. 3 shows the configuration of a switch for operating the first antenna element at the second frequency.
Figure 4 shows the width of the first and second feed taps and the first shorting tab of the first antenna element.
5 shows an embodiment of an antenna having a first antenna element and a second antenna element for MIMO or diversity operation.
Figure 6 shows the configuration of a switch for an antenna to operate at a third frequency.

1 shows an embodiment of an antenna A that may be used in a mobile phone or other wireless device. The antenna A includes a printed circuit board (PCB) having metal wiring on the opposite main side. One of the main sides is covered with a conductive ground plane that can be used as the ground potential (GND). The other major aspect has a metallization that forms part of the first antenna element A1 and the third antenna element A3 to emit and receive electromagnetic energy. The first antenna element A1 operates at the first and second frequencies, and the third antenna element A3 operates at the third frequency. Feed tabs F1, F2, and F3 and shorting tabs S1 and S2 that connect the radiating portion and the receiving portion are perpendicular to both the main sides of the printed circuit board (PCB). Therefore, it is unlikely that the person holding the mobile phone will touch the feed tabs F1, F2, and F3 and the shorting tabs S1 and S2 to change the electrical characteristics. It should be noted that the antenna 1 shown in Fig. 1 is planar and has parts parallel and perpendicular to the main side of the printed circuit board (PCB), which is not essential. The first and third antenna elements A1, A3 can also be configured separately, and can be configured along only two dimensions.

The first antenna element A1 includes a first supply tap F1 for supplying a first frequency, a second supply tap F2 for supplying a second frequency, and a second short- 1 short-circuit tap S1. The first shorting tab S1 is arranged between the first supply tab F1 and the second supply tab F2. In addition, the first antenna element A1 has a tuning slot T arranged between the first shorting tab S1 and the second shorting tab F2. The tuning slot T extends into metal wiring parallel to the main side of the printed circuit board (PCB). The radiation portion and the reception portion of the first antenna element A1 have about a quarter area of the second frequency wave in one direction.

The first antenna element A1 may resonate at the first frequency and the second frequency. The first frequency is 1710 to 2170 MHz and the second frequency is 2300 to 2700 MHz. The first or second frequency is selected by changing the induction operation of the tuning slot (T). The induction operation of the tuning slot T is selected by a plurality of switches, which is shown in Figs. 2 and 3. Fig. Furthermore, the switch is used to supply the first frequency and the second frequency to the first antenna element A1 and is used to change the impedance conversion due to the supply taps F1, F2 and the shorting tap S1.

Fig. 2 shows the configuration of the switches SW1, SW2 and SW3 for operating the first antenna element A1 at the first frequency. The first switch SW1 is opened so that the first frequency supply source U1 is not short-circuited to the ground potential GND. The ground potential (GND) may be the ground plane of the antenna (A). The signal of the first frequency supply source U1 is transmitted to the first supply tap F1 and the radiation part of the first antenna element A1 and is converted into electromagnetic energy.

The second switch SW2 is opened to disconnect the second frequency supply source U2 from the second supply tab F2. Furthermore, the third switch SW3 is closed, and the second frequency supply source U2 is connected to the ground potential GND. The circuit of the second supply tap F2 is opened so that the tuning slot T operates as a series inductor and the inductor is in series with the impedance of the first antenna element A1 except for the tuning slot T. [ As a result, the first antenna element A1 resonates at a frequency of 1710 to 2170 MHz.

Fig. 3 shows a configuration of a switch for operating the first antenna element A1 at a second frequency. The first switch SW1 is closed so that the signal of the first frequency supply source U1 is shunted to the ground potential GND. The second switch SW2 is closed so that the second frequency supply source U2 is connected to the second supply tab F2. The third switch SW3 is opened so that the second frequency supply source U2 is not short-circuited to the ground potential GND.

The series inductance of the tuning slot T is eliminated because the first supply tab F1 is shorted to the ground potential GND and the second supply tab F2 is supplied. The tuning slot T operates in parallel inductance and the inductor is in parallel with the impedance of the first antenna element A1 except for the tuning slot T. [ As the series inductance of the tuning slot T is removed, the first antenna element A1 can resonate at a higher frequency. Moreover, since both the first short-circuiting tap S1 and the first supply tap F1 operate as parallel shunts at the ground potential, the antenna inductance is reduced. The series matching capacitance C1 is connected to a tuning slot operating with parallel inductance to further increase the resonant frequency of the first antenna element A1. In summary, the inductive operation of the tuning slot T is different by using the first supply tap F1 supplying at the first frequency and by using the same tap as the shorting tab when operating at the second frequency.

The first, second and third switches SW1, SW2, SW3 may be any kind of switches. However, it is advantageous to use a MEMS switch because it has a small loss in radio frequency and requires only a small footprint.

The MEMS switch may be galvanic or capacitive. The galvanic switch uses a metal-to-metal contact that, when closed, induces less loss in the broadband. However, a galvanic MEMS switch has only a reduced number of switching cycles. On the other hand, capacitive MEMS switches have the advantage that the contacts are not worn. However, such a switch has a large capacitance which, when closed, should generally be resonated by a small series inductance.

As described above, the series matching capacitance C1 needs to increase the resonant frequency of the first antenna element A1 to operate at the second frequency. If the capacitance is partially provided by the capacitive MEMS switch used as the second switch SW2, this matching capacitance Cl can be reduced in value. If all matching capacitances can be provided by the capacitive MEMS switch SW2, a separate matching capacitance is no longer needed. In this case, the small series inductance used to resonate the RF MEMS switch capacitance is no longer needed. Reducing the number of components for the antenna reduces the size and cost of the antenna.

Fig. 4 is a view showing only a part of the plan view of Fig. 1 showing the first and second supply tabs F1 and F2 and the shorting tab S1 of the first antenna element A1. The first supply tab F1 has a width W1, the second supply tab F2 has a width W2, and the shorting tab S1 has a width WS. When operating at the first frequency, the impedance transformation of the first supply tap F1 and the first shorting tap S1 is determined by adjusting the relative width of W1 to the width of WS, as shown in Fig. 3, the impedance transformation of the taps may be performed such that the relative width of the second supply tab W2 is greater than the combined width of the first supply tab and the first shorting tab W1 + S1 ). Thus, the impedance transforms for the first frequency and the second frequency are independent of each other, which simplifies the design and impedance matching of the first antenna element A1 operating on both frequencies. The width W1S between the first supply tab F1 and the shorting tab S1 and the width WS2 of the tuning slot T also affect the impedance conversion but the influence thereof is difficult to accurately quantify.

FIG. 5 shows an embodiment of an antenna A used in a multiple input / output (MIMO) or antenna diversity system. In a MIMO system, multiple antennas at both the transmitter and the receiver are used to increase data throughput by using high spectral efficiency. In an antenna diversity system, the reliability of a radio link is increased by using independent fading in multiple antenna links. In Fig. 5, the first antenna element A1 is augmented by a second antenna element A2 disposed on the opposite side of the printed circuit board (PCB). The first and second antenna elements A1 and A2 may be used as cellular MIMO, WiMAX MIMO or WiFi MIMO above 1.7 GHz. The first and second antenna elements A1 and A2 can also be used simultaneously with cellular and WiMAX, cellular and WiFi or WiMAX and WiFi without MIMO. Here, cellular may mean GSM, CDMA, UTRA (UMTS, TD-SCDMA, etc.) or any other cellular or mobile system.

Figures 1 and 5 further have a third antenna element A3 used to receive or radiate electromagnetic energy at a third frequency. The third antenna element A3 has a third supply tab F3 for supplying a third frequency and a third shorting tap S3 for shorting the third antenna element A3 to the ground plane. The third antenna element A3 is larger than the first and second antenna elements A1 and A2 and is designed to resonate at a third frequency between 824 and 960 MHz.

6 shows a configuration of a switch for operating the antenna A at the third frequency. The first switch SW1 and the third switch SW3 are closed so that the first frequency supply source U1 and the second frequency supply source U2 are short-circuited to the ground potential GND. The second switch SW2 is opened so that the second frequency supply source U2 is disconnected from the first antenna element A1. The third antenna element A3 is coupled to a third frequency source U3 to radiate electromagnetic energy at a third frequency. Compared to any other arrangement of switches SW1, SW2, and SW3, when the switch is in the arrangement as shown in FIG. 6, the first and third antenna elements A1, Lt; / RTI >

2, 3, and 6 are shown having frequency sources U1, U2, and U3 that drive antenna A, while the ordinary artisan has also shown that antenna A is an antenna that converts electromagnetic energy into electrical signals It should be appreciated that this can be operated in a manner that In addition to the frequency source, there may be a low noise amplifier designed to amplify the signal received at antenna A at the corresponding frequency.

By using the above-described invention, all radio frequency bands of 824 to 2700 MHz can be handled without increasing the antenna size. Each of the first and second antenna elements A1 and A2 covers a frequency of 1710 to 2170 MHz and 2300 to 2700 MHz while the third antenna element A3 covers a frequency of 824 to 960 MHz.

A: antenna A1: first antenna element
A2: second antenna element A3: third antenna element
C1: matching capacitor F1: first supply tab
F2: first supply tab F3: second supply tab
GND: Ground potential PCB: Printed circuit board
S1: 1st paragraph tab S3: 3rd paragraph tab
SW1: first switch SW2: second switch
SW3: Third switch T: Tuning slot
U1: first frequency source U2: second frequency source
U3: Third frequency source W1: Width of the first supply tab
W2: width of the second supply tab WS: width of the first shorting tab
W1S: Width between the first supply tab and the first shorting tab
WS2: Width between the second supply tab and the first shorting tab

Claims (15)

As an antenna,
A first antenna element;
A first supply tab for supplying a first frequency to the first antenna element;
A second feed tab for feeding a second frequency to the first antenna element;
A first shorting tab arranged between the first supply tab and the second supply tab for shorting the first antenna element to a ground potential; And
And a tuning slot arranged between the first shorting tab and the second feeding tab,
Wherein a plurality of switches are provided so that the guiding operation of the tuning slot is varied and the first antenna element is configured to change the induction operation of the tuning slot by changing electromagnetic energy 0.0 > and < / RTI >
The plurality of switches may include:
A first switch having a first connection point coupled to the first supply tap and a first frequency supply and a second connection point coupled to the ground potential;
A second switch having a first connection point coupled to a second frequency source and a second connection point coupled to the second supply tab; And
A third switch having a first connection point coupled to the second frequency supply and a second connection point coupled to the ground potential,
Wherein when the first switch and the second switch are open and the third switch is closed the first supply tab is coupled to the first frequency source and the tuning slot is connected to the first antenna at the first frequency, Lt; RTI ID = 0.0 > inductance, < / RTI >
Wherein when the first switch and the second switch are closed and the third switch is opened, the first supply tab is shorted to the ground potential, the second supply tab is coupled to the second frequency supply source, The tuning slot operates as a parallel inductance to promote resonance of the first antenna at the second frequency.
antenna. delete The method according to claim 1,
And the second switch is coupled to the second supply tab by a matching capacitance. The method of claim 3,
Wherein at least the second switch of the plurality of switches is a capacitive RF micro-electromechanical system (MEMS) switch. 5. The method of claim 4,
Wherein the matching capacitance is provided at least in part by a capacitance of the capacitive RF MEMS switch used as the second switch. The method according to claim 1,
Further comprising a second antenna element corresponding to the first antenna element,
And the second antenna element is arranged on the opposite surface of the printed circuit board on which the first antenna element is arranged. The method according to claim 1,
Further comprising a third antenna element,
Wherein the third antenna element comprises:
A third supply tab for supplying a third frequency to the third antenna element; And
And a third shorting tab for shorting the third antenna element to the ground potential. 8. The method of claim 7,
Wherein the first frequency is between 1710 MHz and 2170 MHz,
The second frequency is from 2300 MHz to 2700 MHz, and
And the third frequency is between 824 MHz and 960 MHz. delete delete delete The method according to claim 1,
And the capacitance of the second switch is selected such that the first antenna element resonates at the second frequency. The method according to claim 1,
Wherein the impedance at the first supply tap is matched to the impedance of the first frequency supply by adjusting the relative width of the first supply tab to the width of the first shorting tab when operating at the first frequency,
Wherein the impedance at the second supply taps is adjusted by adjusting the relative width of the second supply taps to the combined width of the first shorting tab and the first supply taps when operating at the second frequency, Matching the impedance of the source. The method according to claim 1,
Wherein the first antenna element and the second antenna element corresponding to the first antenna element are operated in a multiple-in / multiple-out or diversity manner. The method according to claim 1,
And wherein when operating at a third frequency, said first switch and said third switch are closed and said second switch is open.

Images