KR20020079936A - A hybrid antenna system for a portable wireless communication device - Google Patents

Abstract

A hybrid antenna system for a mobile wireless communications device (WCD) includes a concealed, internal shielded substrate antenna that is fixedly and completely internally mounted to a casing of the mobile WCD. The hybrid antenna system also includes a repositionable antenna, such as a whip antenna, which is optionally expandable and foldable back into the casing. The antenna system electrically connects the repositionable antenna to the movable WCD's internal RF circuitry when the repositionable antenna is in the open position and electrically disconnects the repositionable antenna from the internal RF circuitry when the repositionable antenna is in the refolded position in the casing. It includes mechanisms for doing so.

Description

HYBRID ANTENNA SYSTEM FOR A PORTABLE WIRELESS COMMUNICATION DEVICE

In recent years, the increasing use of personal wireless communication devices (WCDs), such as cellular telephones, has promoted an increasing demand for corresponding antennas for WCD. Many key requirements, including low antenna portion and production cost, compact size, omni-directional gain and adequate frequency bandwidth, high reliability, aesthetic appearance and convenient ergonomic package, facilitate the construction of such antennas with such conditions.

One type of commonly used antenna configuration includes an elongated whip or monopole / dipole antenna. In one known configuration, the antenna is optionally extended from the cellular telephone casing or folded into the cellular telephone. The stretched whip antenna is advantageous in that the spread whip antenna extends away from the cellular telephone and the user's head, maintaining a relatively constant omnidirectional gain even when the user is holding the cellular telephone near his head. Therefore, the whip antenna works well even in relatively low received power situations, eg at the edge of the cell or signal coverage area. On the other hand, the protruding contour of the elongated whip antenna causes disadvantages such as being prone to damage and inconspicuous to the consumer sensitive to appearance.

Cellular telephones are often used with whip antennas and include short helical antennas that are activated when the whip antenna is folded into the casing of the cellular telephone. Spiral antennas, although smaller than whip antennas, are better in appearance and resistant to damage, typically include radiation lengths similar to whip antennas. Nevertheless, the spiral antenna protrudes significantly and permanently from the cellular telephone, which adversely affects the cellular telephone aesthetic and easily damages the spiral antenna.

Thus, cellular telephone manufacturers propose alternatives to whip and spiral antennas that are aesthetically good, such as antennas that are fully internally mounted and protected by the casing of the cellular telephone. Such internally mounted antennas allow cellular telephone manufacturers to construct cellular phones that are aesthetically pleasing and ergonomically acceptable. Since the internal antenna is concealed into the cellular telephone, it works well in relatively high and normal receive signal situations but does not work well in the surrounding coverage area where the received signal power is relatively low. In addition, although better in appearance than whip antennas, internal antennas (and the spiral antennas mentioned above) can be used when the user grabs the casing near the internal antenna and when the user grabs the casing and eventually grabs the internal antenna near the user's head. It is not good because of the opposing antenna gain variation due to loading.

Thus, in an antenna system for a wireless communication device (WCD), there is a need to combine the performance advantages of whip antennas with the external and ergonomic advantages associated with internal antennas and alleviate the disadvantages associated with each of these antenna types.

FIELD OF THE INVENTION The present invention relates generally to antennas, and more particularly to concealable whip antennas and concealed antennas configured for use in mobile wireless communications devices.

1A is a diagram of a first embodiment of a hybrid antenna system in WCD, with the whip antenna in the extended operating position.

FIG. 1B is a diagram of the hybrid antenna system of FIG. 1A, with the whip antenna in a folded non-operational position.

2A is a diagram of a second embodiment of a hybrid antenna system for a WCD, with the whip antenna in an extended operating position and the internal antenna in an inoperative state.

FIG. 2B is a diagram of the hybrid antenna system of FIG. 2A with the internal antenna in operation.

3 is an optional configuration of a hybrid antenna system for the second embodiment, in which the electronic switch is switched between the whip antenna and the internal antenna.

4 is a functional diagram of the electronic switch of FIG.

The present invention provides a moveable hybrid antenna system for WCD. The hybrid antenna system includes a concealed, internally shielded substrate antenna, completely internally and fixedly mounted within the casing of the movable WCD. The hybrid antenna system also includes a repositionable antenna, such as a whip antenna that can optionally extend from the casing and fold into the casing. The antenna system electrically connects the relocatable antenna to the movable WCD's internal RF circuit when the repositionable antenna is in the open position, and electrically repositionable antenna from the internal RF circuit when the repositionable antenna is in the folded position in the casing. Mechanism for blocking.

In a first embodiment, the internal antenna operates in conjunction with the RF circuitry in both the retractable antenna open and folded non-operational positions. Therefore, when the repositionable antenna is in the open position, the internal and repositionable antennas are connected to the RF in parallel, but when the repositionable antenna is in the folded position, only the internal antenna is connected to the RF circuit.

In the second embodiment, only one of the repositionable antenna and the internal antenna at a time is connected to the RF circuit. Specifically, when the relocatable antenna is in the open operating position, only the relocatable antenna is connected to the RF, and when the relocatable antenna is in the folded non-operating position in the WCD, only the internal antenna is connected to the RF circuit. The second embodiment includes two switching configurations. The first configuration includes a mechanical switch for switching between antennas, while the second configuration includes an electronic switch for switching between antennas.

Electrical connections can be directly affected by electrical connections, by inductive or capacitive coupling, or by other effective means.

Features and Benefits

The hybrid antenna system combines the performance advantages of whip antennas with the movable WCD and the cosmetic and ergonomic advantages associated with hidden, internal antennas.

During normal use of the WCD, i.e. when the signal coverage is relatively good, the whip antenna is folded and inactive and hidden inside the WCD casing. In operation, a hidden internal antenna provides satisfactory performance under such conditions. Therefore, most of the time, the WCD maintains a good appearance. However, in the case of poor signal coverage, the user unfolds the higher performance whip antenna to cope with poor signal coverage and expand the usable range of the WCD.

Hybrid antenna systems are constructed in a simple manner using relatively few known components to reduce antenna system manufacturing complexity, cost and size.

The objects, arrangements and effects of the present invention will become more apparent from the following embodiments in conjunction with the accompanying drawings.

1A and 1B, the WCD 100 includes a casing or housing 102, and a first printed circuit board (PCB) 104 is an RF circuit of a WCD mounted or formed on a PCB and in accordance with the present invention. Has a hybrid antenna system. Examples of WCD 100 usable with hybrid antenna 106 include personal digital assistants (PDAs), cellular telephones, PCS phones, and palmtop computers. Casing 102 may be provided in any convenient shape and style, including a "brick-like" or "seashell-like" style used for, for example, a clamshell phone or a flip-top hand-held computer. have.

The hybrid antenna system 106 incorporates a repositionable antenna 108, such as a whip antenna configured in the present invention, and an internal hidden antenna 110, to combine performance advantages with the aesthetic and ergonomic advantages associated with the internal antenna. Include. The hybrid antenna system 106 also includes a first electrically conductive connector 112 and a second electrically conductive connector 14 for connecting the internal antenna 110 and the whip antenna 108 to RF circuits on the PCB 104, respectively. Include. Connectors 112 and 114 are resilient spring clips in the preferred embodiment.

The whip antenna 108 is received slid by the grooves and / or guides of the casing 102 in a known manner. Accordingly, whip antenna 108 may optionally extend from casing 102 and repositionable in the V direction to fold back into casing 102, as described in FIGS. 1A and 1B, respectively. The whip antenna 108 is a unipolar or bipolar radiator of known configuration and includes a radiator that is an electrical conductor having a top 116a and a bottom 116b extended. An insulating sheath 118 covers and electrically insulates the radiator top 116a.

The internal antenna 110 (also referred to as the shielded substrate antenna) is an electrically conductive trace or antenna radiating element 122 formed on the insulation support substrate or the PCB 124 and the signal supply region 126. Include. The PCB 124 fixedly and completely mounted in the casing 102 advantageously keeps the radiating element 122 away from the casing to reduce the antenna loading effect that occurs when the user grabs the WCD 100. Place the WCD near your head during use. The conductive trace may include a plurality of electrically connected traces that form the desired antenna radiating structure. Conductive trace 122 includes conductive pad 128 in signal supply region 126 and provides electrical contact for connecting conductive trace 122 to other circuitry within WCD 100. . Shielded substrate 110 is constructed as set forth in the "multi-layered shielded substrate antenna" filed with the present invention mentioned above.

The PCB 104 fixedly mounted inside the casing 102 has a known RF transceiver and electronic circuits mounted or formed on the PCB to operate the WCD 100. The RF transceiver circuit includes a duplexer 130, a receiving circuit 132, and a transmitting circuit 134 for separating receive and transmit signals. Conductive pads 136 electrically connected to RF circuitry via conductive traces 138 provide electrical contacts for connecting the whip and internal antennas 108 and 110 to the RF circuitry. Providing the RF circuitry and internal antenna 110 on separate PCBs 104 and 124, respectively, advantageously allows more flexibility in configuring each separate PCB and configuring each PCB in the WCD 100. In an optional configuration, the separate PCBs 104 and 124 may be formed on a single PCB or combined into a single PCB having both an internal antenna 110 and an RF circuit (and other electronic circuits) bonded to a single PCB. . The use of such a single PCB advantageously reduces the number of components and simplifies the PCB mounting configuration of the WCD 100.

First elastic spring clip 112 includes opposite ends that are constrained to pads 128 and 136, respectively, to form a fixed electrical connection between internal antenna 110 and RF circuitry on PCB 104. The second resilient spring clip 114 includes a first end 114a secured to the pad 136 and a second repositionable end 114b biased to contact the whip antenna 108. Referring to Figure 1A, when the whip antenna is extended and in operation, the clip end 114b contacts the conductive end of the whip antenna 108 to electrically connect the whip antenna to the RF circuit in parallel with the internal antenna 110. Let's do it.

Referring to FIG. 1B, when the whip antenna is folded and in an inoperative state, the clip end 114b contacts the insulating sheath 118 instead of the conductor 116b, so that the whip antenna is disconnected from the RF circuit (ie, Electrically insulated), and only the internal antenna 110 remains connected to the RF. It will be appreciated that optional whip antenna configurations and mechanisms known for connecting and disconnecting the whip antenna to and from the RF circuitry may be used in the present invention.

During use of the WCD 100, the user places the whip antenna 108 in a folded non-operational position in the casing 102 when the communication signal strength at the WCD is relatively high or at an average level, thereby causing the internal antenna ( 110 only receive and transmit signals. However, if additional antenna performance is needed to cope with bad signal coverage, i.e. when the signal strength in the WCD is relatively low in the suburban or edge signal coverage area, the user places the whip antenna in the extended operating position and thus The whip antenna 108 and the internal antenna 110 both receive and transmit signals.

Hybrid antenna system 106 provides a simple and low cost approach to realizing the combined advantages of whip antenna 108 and internal shielded substrate antenna 110. However, using the extended antenna 108 and the internal antenna 110 together in the paralleled antenna configuration described above may degrade the reception signal performance in the WCD when the antennas 108 and 110 respectively receive signals that interfere with each other. Can be. Therefore, in the embodiments of the present invention to be described below, it is intended to avoid this drawback.

The hybrid antenna system 200 according to the second embodiment of the present invention is described in FIGS. 2A and 2B. For simplicity, the casing 102 and the RF circuit are not shown in FIGS. 2A and 2B. The hybrid antenna system 200 is configured to connect the whip antenna 108 '(similar to the whip antenna 108), the internal antenna 110, the internal antenna 110 and the whip antenna 108', respectively, to the RF circuit. A first electrically conductive resilient connector 202 and a second electrically conductive resilient connector 204. For example, the connectors 202 and 204 and whip antenna 108 'formed of spring clips operate together as a mechanical switching mechanism for electrically connecting and disconnecting each of the antennas 108' and 110 from the RF circuit, as described below. do. The hybrid antenna system 200 advantageously avoids the interference effects mentioned above by electrically connecting only one antenna 108 'or one antenna 110 to the RF circuit at a time.

The whip antenna 108 'includes a conductive end 116b and an opposite end 220 away from the end 116b. Insulating sheath 118 ′ extends between opposite ends 116b and 220. The sheath 118 ′ has a diameter larger than the diameter of the ends 116b and 220. The spring clip 204 is electrically connected to the RF circuit through the conductive pad 206 and the conductive trace 208 formed on the PCB 104 (but presented away from the PCB 104 for simplicity of description). do. The spring clip 204 is sized to reach the end position of the whip antenna 108 'when the whip antenna is in the open position, as shown in FIG. 2A, thereby electrically connecting the whip antenna to the RF circuit. . On the other hand, the spring clip 204 touches the insulating sheath 118 'when the whip antenna 108' is in the folded position, as shown in FIG. 2B, thereby blocking the whip antenna from the RF circuit.

The spring clip 202 is attached to the pad 136 and includes a first end 202b connected to the RF circuit by the conductive trace 210 of the PCB 108. The spring clip 202 has a second repositionable end 202a of the spring clip of the internal antenna 110 when the whip antenna 108 'is in the folded position, as shown in FIG. 2B (and with the dashed line in FIG. 2A). Size adjustments and shapes are formed to bias the contact with the conductive pads 128, thereby connecting the internal antenna 110 to the RF circuit. On the other hand, the sheath 118 'of the whip antenna 108' is in contact with the spring clip 202 when the whip antenna is in the extended position, as shown in FIG. 128) to isolate the whip antenna from the RF circuitry. Thus, when the whip antenna is in the open or folded position, only one of the whip antenna 108 'or internal antenna 110 is electrically connected to the RF circuit.

An optional hybrid antenna system 300 according to the second embodiment is shown in FIG. Hybrid antenna system 300 uses a combination of mechanical and electrical switching techniques to selectively connect whip antenna 108 or internal antenna 11 to RF circuitry. Hybrid antenna system 300 selectively selects whip antenna 108 to conductive trace 304 on PCB 104 in a manner similar to that described with FIGS. 1A and 1B when the whip antenna is in the open and folded positions, respectively. Mechanical connectors 302 for electrical connection and disconnection. Internal antenna 110 is electrically connected to conductive trace 306 on PCB 104 using a fixed electrical connection similar to the manner described with reference to FIGS. 1A and 1B.

Hybrid antenna system 300 includes a first input 320 connected to conductive trace 304, a second input 322 connected to conductive trace 306 and an output 324 connected to the RF circuit (collectively). Electronic switch 310 on PCB 104 having the reference numeral 330. The electronic switch 310 optionally selects the first input 320 and thus the whip antenna 108 or the second input 322 when the whip antenna is in the extended operating position and the folded non-operating position, respectively. The internal antenna 110 is connected to the RF circuit 330.

A detailed view of the electronic switch 310 is shown in FIG. Electronic switch 310 includes switching element 340 functionally described in FIG. Switching element 340 outputs 324 (shown in solid line) or input 322 (shown in dashed line) in response to a switching control voltage applied to switching element 340 via select line 342. ). The switching element 340 may be implemented using a switching pin diode controlled by a switching control voltage as is known in the art. The electronic switch 310 also senses when the whip antenna 108 is connected to the input via the connector 302 and the PCB trace 304 and the switching control applied to the switching element 340 in response to the sensed load. Antenna load sensing circuit 346 for inducing voltage. The supply voltage Vcc and the reference potential Gnd are applied to the terminals 350 and 352 of the switch 310, respectively, to drive the electronic switch 310.

In operation, the antenna load sensing circuit 346 senses, for example, 50 or 70 ohms of antenna load when the whip antenna 108 is stretched and connected to the input 320 by the connector 302 to operate. In response, the sense circuit 346 applies an appropriate control voltage to the switching element to connect the whip antenna 108 to the RF circuit 330 (as shown by the solid line in FIG. 4). On the other hand, the antenna load sensing circuit 346 senses the lack of antenna loading when the whip antenna 108 is folded and blocked from the input 320 by the connector 302. In response, the sense circuit 346 applies an appropriate control voltage to the switching element 340 to isolate the whip antenna 108 from the RF circuit 330 and the internal antenna 108 to the RF circuit. 330 (as shown by the dotted line in FIG. 4).

While various embodiments of the invention have been described, it will be understood that the scope of the invention is not limited thereto. It is intended that the scope of the invention be interpreted as the broadest range consistent with the scope defined by the interpretation of the appended claims.

Claims (14)

An antenna system for a mobile communication device, A first antenna mounted completely inside the casing of the movable communication device; A second antenna that can optionally be folded and folded within the casing; And A first connection for connecting the second antenna to the internal RF circuitry of the movable communication device when the second antenna is in the open position and for electrically disconnecting the second antenna from the internal RF circuitry when the second antenna is in the folded position An antenna system comprising means. The method of claim 1, wherein the second connection means for selectively connecting the first antenna to the RF circuit when the second antenna is in the folded position, and disconnecting the first antenna from the RF circuit when the second antenna is in the open position. Antenna system further comprising. The method of claim 2, wherein the second connection means comprises a switching circuit, the switching circuit detects an impedance of the second antenna, and disconnects the first antenna from the RF circuit when the predetermined impedance is detected at the second antenna. Antenna system. 3. The antenna system of claim 2 wherein the second connecting means comprises an electrically conductive resilient connector for connecting the first antenna to the internal RF circuit when the second antenna is in the folded position. 5. The connector of claim 4, wherein the resilient connector is in contact with a fixed end electrically connected to an internal RF circuit, and when the second antenna is in a folded position, thereby contacting the first antenna to thereby electrically connect the first antenna to the RF circuit. And a repositionable end biased to cause said repositionable end to be relocated away from said first antenna when said second antenna is in the open position thereby to disconnect said first antenna from internal RF circuitry. The antenna system of claim 1 wherein the fixed electrical connector electrically connects the first antenna to the internal RF circuit both when the second antenna is in the extended and folded positions. The antenna system of claim 1 further comprising a printed circuit board (PCB) on which components of an internal RF circuit are formed, wherein the first antenna is formed on the PCB. The method of claim 1, A first printed circuit board (PCB) on which components of an internal RF circuit are formed; And And a second PCB on which the first antenna is formed. The antenna system of claim 1 wherein the second antenna is one of a monopole and dipole whip antenna comprising an extended radiator. The antenna system of claim 1 wherein the first antenna is a shielded substrate antenna comprising electrically conductive traces formed on a printed circuit board secured within a casing of a WCD. In a wireless communication device (WCD) that includes an internal RF circuit, A method of operating a hybrid antenna system comprising a first shielded substrate antenna fully fixedly mounted in a casing and a second repositionable antenna that can be selectively unfolded and folded within the casing of the WCD. Electrically connecting the second antenna to the internal RF circuitry of the WCD when the second antenna is in the extended position and electrically disconnecting the second antenna from the internal RF circuit when the second antenna is in the folded position; And Electrically connecting the first antenna to the internal RF circuitry when the second antenna is in the collapsed position. 12. The method of claim 11 further comprising electrically disconnecting the first antenna from the internal RF circuitry when the second antenna is in the extended position. 13. The method of claim 12 further comprising detecting an impedance of the second antenna greater than zero and disconnecting the first antenna from the RF circuit if the impedance of the second antenna is detected. 13. The method of claim 12, further comprising electrically connecting and disconnecting the first antenna to and from the internal RF circuit when the second antenna is folded and extended using elastic electrical contact. .