US20080194302A1

US20080194302A1 - Mobile phone with an antenna structure having improved performance

Info

Publication number: US20080194302A1
Application number: US11/749,596
Authority: US
Inventors: Jesus Alfonso Castaneda; Seema B. Anand
Original assignee: Broadcom Corp
Current assignee: Avago Technologies International Sales Pte Ltd
Priority date: 2007-02-12
Filing date: 2007-05-16
Publication date: 2008-08-14
Also published as: US7817969B2; US20080194288A1; US20080192807A1

Abstract

A mobile phone with a FM antenna structure having improved FM performance in a mobile phone. The mobile phone includes a printed FM antenna having a planar structure less than a planar area of the mobile phone, a conductive layer providing a ground plane to the printed FM antenna, the conductive adjacent the printed FM antenna in an electrostatic field relation; and a battery having a planar surface positioned adjacent an opposite side of the conductive layer. The planar structure of the printed FM antenna and the planar surface of the battery are substantially parallel to each other in a spaced-apart relation improving the FM performance of the printed FM antenna.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser. No. 60/889,528 entitled “Mobile Phone with an Antenna Structure having Improved Performance,” filed Feb. 12, 2007, which is hereby incorporated herein by reference in its entirety for all purposes.

SPECIFICATION

1. Technical Field
The present invention relates to wireless communications and, more particularly, signal reception and transmission in mobile wireless communication systems.
2. Related Art
Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards, including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a mobile telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, et cetera, communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channels (for example, one of a plurality of radio frequency (RF) carriers of the wireless communication system) and communicate over that channel(s). For indirect wireless communications, each wireless communication device communicates directly with an associated base station (for example, for cellular services) and/or an associated access point (for example, for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via a public switch telephone network (PSTN), via the Internet, and/or via some other wide area network.
Each wireless communication device includes a built-in radio transceiver (that is, a receiver and a transmitter) or is coupled to an associated radio transceiver (for example, a station for in-home and/or in-building wireless communication networks, RF modem, et cetera). As is known, the transmitter includes a data modulation stage, one or more intermediate frequency stages, and a power amplifier stage. The data modulation stage converts raw data into baseband signals in accordance with the particular wireless communication standard. The one or more intermediate frequency stages mix the baseband signals with one or more local oscillations to produce RF signals. The power amplifier stage amplifies the RF signals prior to transmission via an antenna.
An antenna is an essential element for a wireless communication device. The antenna provides a wireless interface for the wireless communication device, which may be a radio, mobile phone, pager, station (for wireless local area network, wireless internet, et cetera). The particular type of wireless communication system, which prescribes the transmission frequencies, reception frequencies and power levels, dictates the performance requirements for the antenna.
Because most wireless communication devices are handheld or portable devices, each component comprising these devices must be small, efficient, economical and lightweight. The antenna is no exception—it too must be small, efficient, economical and lightweight. To achieve these requirements, many antennas have been developed having various structures including monopole, dipole, et cetera.
The diminutive size of the antennas, however, leave them more susceptible to environmental changes that correspondingly affect the ability of an antenna to reliably receive and/or transmit signals. For example, mobile phones can be readily held within the grasp of a user, or placed within a pocket, et cetera. When environmental conditions change, the impedance and consequently the ability of the antenna are adversely affected, reducing the signal-to-noise performance of the antenna.
Although favorable environmental conditions may return, a user becomes frustrated by the inconsistency of the service for their mobile phone or device. Also, the compactness of mobile wireless devices can cause E-M interference between other device components, further degrading antenna performance. Accordingly, various types of antennas and corresponding shapes provide adequate antenna performance. Nevertheless, they become becoming increasingly sensitive to environmental changes and interference from other device components. Therefore, a need exists for a printed antenna structure for a mobile phone that improves the performance of the increasingly sensitive antennae in such adverse environmental conditions.

SUMMARY

The present invention is directed to apparatus and methods of operation that are further described in the following Brief Description of the Drawings, the Detailed Description of the Drawings, and the claims. Other features and advantages of the present invention will become apparent from the following detailed description of the drawings made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when the following detailed description of the preferred embodiment is considered with the following drawings, in which:

FIG. 1 is a functional block diagram illustrating a communication system that includes a plurality of base stations or access points (APs), a plurality of wireless communication devices and a network hardware component;

FIG. 2 is a schematic block diagram illustrating a wireless communication device architecture including an FM transceiver and an FM antenna tuning module according to an embodiment of the present invention;

FIG. 3 is a schematic block diagram illustrating a wireless communication device architecture including an FM transceiver an FM antenna tuning module coupled with a tuning circuit according to an embodiment of the present invention;

FIG. 4 is an exploded view of a mobile phone with a brick configuration that includes an antenna structure according to an embodiment of the present invention;

FIG. 5 is an exploded view of a mobile phone with a clamshell configuration that includes an antenna structure according to an embodiment of the present invention;

FIG. 6 is a cross-sectional diagram of an antenna structure including a printed FM antenna in a first orientation according to an embodiment of the present invention;

FIG. 7 is a cross-sectional diagram of an antenna structure including a printed FM antenna in a second orientation according to another embodiment of the invention;

FIG. 8 is an exploded view of another antenna structure including a dielectric spacer according to a further embodiment of the present invention;

FIG. 9 is a cross-sectional diagram of the antenna structure of FIG. 8; and

FIG. 10 is a flow diagram of a method of providing an antenna structure for a mobile phone according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating a communication system that includes circuit devices and network elements and operation thereof. More specifically, a plurality of network service areas 04, 06 and 08 are a part of a network 10. Network 10 includes a plurality of base stations or access points (APs) 12-16, a plurality of wireless communication devices 18-32 and a network hardware component 34. The wireless communication devices 18-32 may be laptop computers 18 and 26, personal digital assistants 20 and 30, personal computers 24 and 32 and/or mobile telephones 22 and 28.
The base stations or APs 12-16 are operably coupled to the network hardware component 34 via local area network (LAN) connections 36, 38 and 40. The network hardware component 34, which may be a router, switch, bridge, modem, system controller, et cetera, provides a wide area network connection 42 for the communication system 10 to an external network element. Each of the base stations or access points 12-16 has an associated antenna or antenna array to communicate with the wireless communication devices in its area. Typically, the wireless communication devices 18-32 register with the particular base station or access points 12-16 to receive services from the communication system 10. For direct connections (that is, point-to-point communications), wireless communication devices communicate directly via an allocated channel.
Some or all of the wireless communication devices 18-32 may include a FM transceiver to receive and/or transmit continuous waveform signals in the FM frequency broadcast band, which in the United States is 87.9 to 107.9 MHz. It can be appreciated, however, that FM may be transmitted on any frequency. In the present example, wireless communication devices 22, 24, 28, 30, and 32 include FM transceivers 23, 25, 31, 33, and 35, respectively. In this manner, the wireless communication devices may receive and/or transmit media content via FM frequency transmission techniques.
In addition to media content (such as audio, video, et cetera), a wireless communication device may receive and/or transmit additional information such as Radio Data System (“RDS”) information, which provides small amounts of digital information via FM radio broadcasts. This information can include items such as time, track/artist information, station identification, et cetera.
FM broadcast stations 54 and 56 transmit media content over continuous waveforms in the FM band, in which the FM transceivers 23-33 receive via their respective FM antennas. The FM transceivers then process the signals for playback of the media content to a user device. Also, the wireless communication devices may transmit FM signals as a local broadcast to nearby audio devices having FM receivers, such as personal stereos, automobile FM radios, et cetera.
The small wireless devices receive correspondingly-sized FM antennas having an antenna structure, which improves the antenna performance across non-ideal environmental conditions for the small wireless device. In general, a human body proximate to an FM antenna affects the impedance of the FM antenna (such as the wireless device being clasped in a user's hand, stored in a pocket, notebook, et cetera). As a person moves either closer to or further away from an antenna, the change in the relative position of the person proximate to the antenna causes the impedance of the antenna to change. A human body also absorbs the radio frequency waves, affecting the electric field and the magnetic field of the RF wave. Because the FM antennas are reduced to fit within a smaller wireless device, the antenna impedances become more sensitive to these varying environmental conditions.
As a result, the varying antenna impedances resulting from the non-ideal environmental conditions affect the signal processing and media content playback to a user. For example, when reception conditions are less than ideal (that is, the signal-to-noise ratio worsens), a stereo FM broadcast playback is in mono, or the FM signal may be dropped altogether. With ever varying environmental conditions, the varying and/or inconsistent playback frustrates users. These antenna structures are discussed in greater detail with reference to FIGS. 2 through 10.
FIG. 2 is a schematic block diagram illustrating a wireless communication device 22-32. As illustrated, wireless communication device 22-32 includes a digital processing module 54, a memory 56, user interface(s) 52, transceivers 58-66, an FM antenna tuning module 68, a printed FM antenna 70, and the antenna switch 72. The digital processing module 54 and memory 56 execute instructions and perform corresponding communication functions in accordance with a particular mobile and/or cellular phone standard.
User interface(s) 52 allows data to be received from and provides connectivity to an output device such as a display, monitor, speakers, microphone, et cetera, such that the received data may be displayed and/or presented. The digital processing module 54 may also receive the outbound data from an input device such as a keyboard, keypad, microphone, et cetera, via the user interface(s) 52 or generate the data itself. The user interface provides outbound data 76 to the digital processing module 54 for transmission via one of the transceivers 58-66. The user interface also receives inbound data 74 destined for a user.
The wireless communication device 22-32 includes several transceivers (that is, receiver and transmitter) for accommodating different communication and/or data sessions. The wireless communication device 22-32 includes a cellular transceiver 58 (for example, Personal Communication System (PCS), Global System for Mobile Communications (GSM), Wideband CDMA, et cetera), a Wireless Wide Area Network (WWAN) transceiver 60 (for example, WiMAX, HSDPA, et cetera), a Wireless LAN (WLAN) transceiver 62 (for example, IEEE 802.11), a Wireless Personal Area Network (WPAN) transceiver 64 (for example, Bluetooth, IEEE 802.15, et cetera), and a FM transceiver 66.
The transmitter portion of a transceiver generally includes a data modulation stage, one or more intermediate frequency stages, and a power amplifier stage. The data modulation stage converts raw data into baseband signals in accordance with the particular wireless communication standards specification. The one or more intermediate frequency stages mix the baseband signals with one or more local oscillations to produce RF signals. The power amplifier stage amplifies the RF signals prior to transmission via an antenna.
A transceiver receiver portion generally includes a low noise amplifier (LNA) stage, one or more intermediate frequency stages, and a data demodulation stage. The LNA stage amplifies the received RF signals for providing a stronger signal for subsequent processing. The one or more intermediate frequency stages mix the RF signals with one or more local oscillations to produce baseband signals, in accordance with the particular wireless communication standards specification. In other transceiver configurations, a received FM signal may be converted directly to baseband signals. The data demodulation stage operates to convert the baseband signals into raw data.
The transceivers 58-64 receive and transmit RF signals via the antenna switch 72, which operates to couple the receivers to the antenna 86 in a receive mode, and to couple the transmitters in a transmit mode. The antenna switch 72 provides a many-to-one access to the antenna 86 for providing efficient use of antenna resources. Examples of antenna switches are discussed in further detail in U.S. Pat. No. 7,079,816, entitled “On Chip Diversity Antenna Switch,” issued Jul. 18, 2006, which is hereby incorporated herein by reference.
The FM transceiver 66 receives continuous waveform signals 89 from an FM transmitter, such as FM broadcast stations 54 and 56 (see FIG. 1), via the printed FM antenna 70. Also, the FM transceiver 66 may transmit a continuous waveform signal 89 in the FM band to a local receiver (such as a personal stereo, automobile FM radio, et cetera).
An FM antenna tuning module 68, including a tuning circuit 69, operates to adjust the impedance match with the printed FM antenna 70 with an impedance adjustment value 73. In general, the smaller the “footprint” of an FM antenna, the more vulnerable its performance is due to its positioning within a wireless communication device with respect to other components, and more sensitive to changes in its operational environment that adversely affect the tuning of the antenna 70 (such as by the varying proximity of a user to the wireless communication device).
The printed FM antenna 70 may be provided under a variety of configurations, such as a monopole antenna, a dipole antenna (for example, such as the dipole antenna depicted in U.S. Pat. No. 7,034,770, entitled “Printed Dipole Antenna,” issued Apr. 25, 2006, which is hereby incorporated herein by reference), an eccentric spiral antenna (for example, such as the eccentric spiral antenna depicted in U.S. Pat. No. 6,947,010, entitled “Eccentric Spiral Antenna,” issued Apr. 4, 2000, which is hereby incorporated herein by reference), a fractal element antenna, et cetera. Each configuration may have different design considerations.
As an example, a monopole antenna may have improved performance over a dipole antenna structure due to the lower ohmic loss of the antenna traces (that is, less antenna traces can be used with a monopole structure). In general, a lower ohmic loss provides the printed FM antenna 70 with higher antenna efficiency.
The monopole structure relies on the existing ground of the mobile phone 22 to generate an image of the “missing” portion (that is, the “dipole” portion for the monopole antenna). Because the wireless device may not have a perfect ground available for attachment of a monopole antenna structure, the impedance matching may be unpredictable. The overall performance of a monopole antenna, however, may improve due to the lower ohmic loss of the antenna trace 218 with respect to small antenna “footprints”.
Lower ohmic loss for an antenna may also be recognized by operating an antenna at a higher resonant frequency. For example, the printed FM antenna 70 has a higher resonant frequency (such as 2-3 times higher) than the intended operational frequency (in the present example, the FM frequency band). The higher resonant frequency permits the electrical length of the antenna to be reduced, and correspondingly, the amount of space allocated for the antenna trace. That is, a shorter electrical length has fewer trace windings that can have larger trace surfaces in a given antenna area—the result is a lower ohmic loss. In operation with the FM transceiver 66 can then reduce the resonant frequency of the printed FM antenna 70 to the intended frequency resonance using discrete (or lumped) low-loss antenna matching components.
A trade off, however, exists between the highest resonant frequency to which the antenna is tuned versus the amount of impedance matching (via the FM antenna tuning module 68) to bring the resonant frequency within the desired operational frequency. For instance, when the antenna resonates at a very high frequency, the required amount of impedance matching is excessive, consequently producing excessive antenna loss. In other words, the advantage of having a lower ohmic loss and higher antenna efficiency is lost. On the other hand, when the antenna resonates substantially close to the desired resonant frequency, little matching components would be needed, but the resulting ohmic loss of the resulting FM antenna trace would be comparable or larger than the radiation resistance for the FM antenna 70.
The FM antenna tuning module 68 operates to tune the printed FM antenna 70 within the desired operational frequency. The FM antenna tuning module 68, based upon a signal strength indication of a received continuous wavelength signal 89, provides an adjustment control signal to the tuning circuit 69. The tuning circuit 69 correspondingly varies the impedance (and the resonance frequency) of the printed FM antenna 70 via an impedance adjustment value 73. The tuning circuit 69 includes voltage-controlled variable impedance devices (such as varactors or varicap diodes) to produce the impedance adjustment value 73. That is, by adjusting the impedance value through the tuning circuit 69, the FM antenna tuning module 68 tunes the printed FM antenna 70 to the operational conditions of the wireless communication device 22-32.
The FM antenna tuning module 68 has at least two tuning modes: a frequency recovery mode and a tracking tuning mode.
Under the first mode, the FM antenna tuning module 68 enters the frequency recovery mode either upon startup of the wireless device, or upon a complete loss of an FM signal (such as when entering an underground tunnel). In the frequency recovery mode, the tuning module 68 operates to establish a stronger FM signal by centering the frequency of the printed FM antenna 70 based upon a signal strength indication. When an FM signal is established (as reflected by the signal strength indication), the tuning module 68 determines the frequency associated with the selected FM antenna tuning. Based upon a delta frequency value for a desired FM channel versus a known FM channel, the tuning module 68 modifies the tuning of the antenna via the tuning circuit 69 to produce the impedance adjustment value 73.
Under the second, or tracking, mode, the tuning module 68 continuously tracks variations of the signal such as those caused by changes in the device's environment, which may cause the FM antenna tuning to vary at a slow rate (for example, less than 10 kHz). The tracking function of the tuning module 68 operates to dither the antenna tuning at incremental steps (for example, about 0.2 MHz steps) and sampling the continuous waveform signal strength at the dithered frequency. The dither rate is one outside the range of a user hearing range (for example, about 20 Hz to about 20 kHz) to minimize audible detection of the operation by a user.
The FM antenna tuning module 68 and the tuning circuit 69 may be on a single integrated circuit or a plurality of integrated circuits. Also, the FM antenna tuning module and the tuning circuit 69 may be implemented as part of a system on a chip. Examples of other implementations are discussed in detail with reference to FIG. 3. A discussion of the antenna structures are discussed in further detail with reference to FIGS. 4 through 10.
The digital processing module 54, in combination with operational instructions stored in memory 56, executes digital receiver and transmitter functions. The digital processing module 54 may be implemented using a shared processing device, individual processing devices, or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on operational instructions.
Memory 56 may be a single memory device or a plurality of memory devices. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, and/or any device that stores digital information. Note that when digital processing module 54 implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory storing the corresponding operational instructions is embedded with the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. Memory 56 stores, and digital processing module 54 executes, operational instructions corresponding to at least some of the functions illustrated and/or described herein.
In operation, the digital processing module 54 processes outbound data 76 in accordance with a particular wireless communication standard (for example, IEEE 802.11a, IEEE 802.11b, Bluetooth, IEEE 802.16, et cetera) to produce the appropriate digital transmission formatted data for a present communication session, which includes cellular data 59, WLAN data 61, WWAN data 65, and/or FM signal data 67. This data will be a digital baseband signal or a digital low IF signal, where the low IF typically will be in the frequency range of one hundred kilohertz to a few megahertz.
Each respective transceiver 58-66 converts the digital data from the digital domain to the analog domain. Though the antenna 86 is schematically depicted as external to the body of the radio, commercial versions of the wireless communication device generally incorporate the antenna element and structures within the body of the device. Also, the wireless communication device may also include additional antennas for standards specific applications, such as those for Bluetooth applications, et cetera.
As one of average skill in the art will appreciate, the wireless communication device of FIG. 2 may be implemented using one or more integrated circuits. For example, the digital processing module 54 and memory 56 may be implemented on a second integrated circuit, and the remaining components of the wireless communication device 22-32, less antenna 86, may be implemented on a third integrated circuit. As an alternate example, the wireless communication device 22-32 may be implemented on a single integrated circuit.
FIG. 3 is a schematic block diagram illustrating a wireless communication device 22-32 that includes a distributed embodiment of the FM antenna tuning module 68 and the tuning circuit 69, and multiple antenna switches 75 and 76 coupled to the antennae 86.
As illustrated, the wireless communication device 22-32 includes a digital processing module 54 and a memory 56. The digital processing module 54 and memory 56 execute instructions and perform corresponding communication functions in accordance with a particular mobile and/or cellular phone standard. To the extent that like components and/or elements have been earlier described of the wireless communication device 22-32, the description will not be repeated here with respect to FIG. 3.
The wireless communication device 22-32 includes antenna switch 75 and antenna switch 77. Antenna switch 75 services the cellular Tx/Rx signal 81 and the WWAN Tx/Rx signal 83 for transmission and/or reception modes over the antenna 86. Antenna switch 77 services the WLAN Tx/Rx signal 85 and WPAN Tx/Rx signal 87 for transmission and/or reception modes over the antenna 86. The FM transceiver 66 receives and/or transmits a continuous wavelength signal 89 via the printed antenna 70.
Multiple antenna switches 75 and 77 permit each of the antenna switches to accommodate the characteristics of similar communications modes. Examples of characteristics may include similar frequency bands, similar data rates, et cetera. For example, an antenna switch may service cellular frequency bands (such as for AMPS, IS-95 (CDMA), IS-136 (D-AMPS), GSM, operating in the 824-849 MHz, 869-894 MHz, 896-901 MHz, and 935-940 MHz frequency bands), and another antenna switch may service Personal Communication Service (“PCS”) frequency bands (such as for GSM, IS-95 (CDMA), IS-136 (D-AMPS), operating in the 1850-1910 MHz and 1930-1990 MHz frequency bands). A further antenna switch may service high-data rate communications (such as 2.4 GHz).
The FM transceiver 66 receives from the printed FM antenna 70 the continuous wavelength signal 89 via the printed FM antenna 70. The FM antenna tuning module 68 receives from the FM transceiver 66 a signal strength indication (SSI). When the SSI falls outside a permissible signal strength level, the tuning circuit 69 provides an impedance adjustment value 73 to the printed FM antenna based upon the tuning data 71 from the FM antenna tuning module 68.
The tuning circuit 69 is illustrated as provided on a separate IC with respect to the FM transceiver 66 and the FM antenna tuning module 68. In this manner, differing fabrication processes may be used to implement the voltage-controlled variable impedance devices of the tuning circuit 69 and with processes to implement other components of the wireless communication device 22-32. That is, in some instances, a reduction in fabrication cost and complexity may be realized. Also, wireless communication devices may have an impedance bank accessible to other components within the device to permit shared access to those components (for example, for clock adjustment, et cetera). By adjusting the impedance value of the tuning circuit 69, the FM antenna tuning module 68 times the printed FM antenna 70 to an impedance of a communications device 22-32.
FIG. 4 is an exploded view of a mobile phone 22 having an antenna structure 200. The mobile phone 22 has a structure sometimes referred to as a “brick.” The mobile phone 22 includes a case face cover 202, a case back cover 222, and a battery cover 228. The case face cover 202 includes a display 204, a function keypad 206, and a numeric keypad 208. The case face cover 202 receives a printed circuit board 210 having integrated circuits 212, which include transceivers 58-66 (such as that discussed with reference to FIGS. 2 and 3) that is coupled to a printed FM antenna 70 of the antenna structure 200.
Further, the printed circuit board 210 may include lumped tuning components to initially match the impedance of the mobile phone 22 with the printed FM antenna 70. The case back cover 222 includes a first side 219 and a second side 221. The second side 221 defines a sloped portion 223 to receive the battery cover 228.
The mobile phone 22 supports different forms of communication and information and/or media content. For example, in addition to supporting voice calls, the mobile phone 22 can also send and receive data, send text messages via a Short Messaging Service (“SMS”), access Wireless Application Protocol (“WAP”) services, provide Internet access through data technologies such as General Packet Radio Service (“GPRS”), sending and receiving pictures with built-in digital cameras, video and sound recording, et cetera. Additionally, local features may be available with the mobile phone 22 such as alarms, volume control, user defined and downloadable ring tones and logos, interchangeable covers, et cetera.
The antenna structure 200 includes the printed FM antenna 70, a conductive material forming a ground plane 224, and the battery 226. The printed FM antenna 70 includes an antenna trace 218, and an input/output connection 216. The printed FM antenna 70 has a planar structure that is less than a planar area of the battery cover 228, and is positioned adjacent the inside of the battery cover 228. The printed FM antenna 70 may have a variety of configurations that are designed according to varying criteria, as discussed with respect to FIG. 2.
Also, the printed FM antenna 70 may be implemented on one or more printed circuit board layers and/or one or more integrated circuit layers. The coupling of the transceiver circuitry of the integrated circuits 212 with the printed FM antenna 70 may be direct or indirect and positioned on the printed FM antenna 70 to achieve a desired load impedance. For example, the input/output connection 216 may be a coaxial probe, a printed microstrip, a waveguide, and a coplanar transmission line, et cetera.
A battery 226 has a planar structure and is positioned adjacent a second side of the ground plane 224, such that the planar structure of the printed antenna 70 and of the battery 226 are substantially parallel. The ground plane 224, which is positioned between the battery 226 and the printed FM antenna 70, operates to improve a signal-to-noise performance of the printed FM antenna 70. The battery 226 may have a conductive outer layer that provides the ground plane 224 to the printed FM antenna 70. The battery cover 228, case back cover 222, and the case face cover 202 couple to provide the electrical and physical connectivity for operation of the mobile phone 22.
FIG. 5 is an exploded view of a mobile phone 28 having an antenna structure 200. The mobile phone 28 has a structure sometimes referred to as a “clamshell” structure. The mobile phone 28 supports different forms of communication and media information content. For example, in addition to supporting voice calls, the mobile phone 28 can also send and receive data, send text messages via a Short Messaging Service (“SMS”), access Wireless Application Protocol (“WAP”) services, provide Internet access through data technologies such as General Packet Radio Service (“GPRS”), sending and receiving pictures with built-in digital cameras, video and sound recording, et cetera. Additionally, local features may be available with the mobile phone 28 such as alarms, volume control, user defined and downloadable ring tones and logos, interchangeable covers, et cetera.
The mobile phone 28 includes a first portion 242 and a second portion 250. The first portion 242 includes a keypad 244, a function keypad 246, and a case face cover 254. The first portion 242 also receives a printed FM antenna 70, and a battery 226, each of which being separated by a ground plane 224. The battery 226, ground plane 224, and the printed FM antenna 70 may be formed as a unit with the back cover 229. The second portion 250 of the mobile phone 28 includes a display 248 for relaying call status and other information that may be retrieved and presented to the user. The first portion 242 and the second portion 250 fold along a hinge portion 251 to a substantially parallel position when placed in a closed position.
The mobile phone 28, via the first portion 242, receives a printed circuit board 210 having integrated circuits 212, which include transceiver circuitry 58-66 (such as that discussed with reference to FIGS. 2 and 3). The FM transceiver 66 (see FIGS. 2 and 3) is coupled to the printed FM antenna 70.
The first portion 242 of the clamshell structure provides a smaller footprint space and/or area for the printed FM antenna 70. Accordingly, the performance of the printed FM antenna is more readily influenced by changes in its operational environment by impedance changes caused by a user and/or other objects. In this regard, the ground plane 224 serves to mitigate these influences and to further improve the performance of the printed FM antenna with respect to signal reception. Also, the printed circuit board may include lumped tuning components, which compensate for impedances introduced by the mobile phone components, initially tuning the printed FM antenna 70 to the wireless communication device 22-32.
The printed FM antenna 256 includes an antenna trace 252, and an input/output connection 258. The printed FM antenna 70 has a planar structure that is less than a planar area of the first portion 242 of the phone 28, and is positioned adjacent the ground plane 224. The printed FM antenna 70 may be implemented on one or more printed circuit board layers and/or one or more integrated circuit layers. The coupling of the transceiver circuitry of the integrated circuits with the printed FM antenna 70 may be direct or indirect, and positioned on the printed FM antenna 70 to achieve a desired load impedance. For example, the input/output connection 216 may be a coaxial probe, a printed microstrip, a waveguide, and a coplanar transmission line, et cetera.
The printed FM antenna 70 may be provided under a variety of configurations depending upon the desired operational characteristics. Examples of the varying configurations are discussed in detail with respect to FIG. 2.
The battery 226 has a planar structure that is positioned adjacent a second side of the ground plane 224, such that the planar structure of the printed FM antenna 70 and of the battery 226 are substantially parallel to each other in a spaced apart relation to improve the performance of the printed FM antenna 70. The battery 226, ground plane 224, printed FM antenna 70, and back cover 229 may be integrated into a module that detachably couples with the first portion 242 to provide the electrical and physical connectivity for operation of the mobile phone 28. Further, the ground plane 224 may be formed as a conductive layer to the battery 226.
FIG. 6 is a cross-sectional diagram of the antenna structure 200. The antenna structure 200 includes the printed FM antenna 70 and the battery 226 with the ground plane 224 in a layered relation. The antenna trace 218 is electrically insulated from the ground plane 224 by a protective layer 225. The printed FM antenna 70 has a planar structure that is less than a planar area defined by the outer periphery of the mobile phone battery cover 228, and is positioned such that the antenna substrate 219 is adjacent the inner side of the battery cover 228. The antenna trace 218 is oriented towards the ground plane 224.
The antenna substrate 219 may be formed with the battery cover 288, and further may be coupled to, or form a portion of, the inner surface of the battery cover 228. The protective layer 225 and the antenna substrate 219 are made of a dielectric material that provides electrical insulation between mobile phone components while supporting electrostatic fields. Further, the dielectric material has a dielectric constant sufficient to concentrate electrostatic lines of flux while dissipating minimal energy in the form of heat. Examples of materials include air, polyethylene, polystyrene, et cetera. The planar structure of the printed FM antenna 70, the ground plane 224, and the planar surface of the battery 226 are substantially parallel to each other. The sandwiched structure provides improved FM signal reception for the printed FM antenna 70.
FIG. 7 is a cross-sectional diagram of the antenna structure 239. The antenna structure 239 illustrates another sandwich structure that may be used in the mobile phones 22 and/or 28. The antenna structure 200 includes the printed FM antenna 70 and the battery 226 with the ground plane 224 in a layered relation. The antenna trace 218 is electrically insulated and/or mechanically protected by a protective layer 225. The printed FM antenna 70 has a planar structure that is less than a planar area defined by the outer periphery of the mobile phone battery cover 228, and is positioned such that the antenna substrate 219 is adjacent the ground plane 224. The antenna trace 218 is adjacent the inner surface of the battery cover 228. Accordingly, The planar structure of the printed FM antenna 70, the ground plane 224, and the planar surface of the battery 226 are substantially parallel to each other. The sandwiched structure provides improved FM signal performance for the printed FM antenna 70.
FIG. 8 is an exploded view of a further antenna structure 230 implementing a dielectric spacer 257. The antenna structure 230 may be used in the brick structure of the mobile phone 28 and/or the clamshell structure of the mobile phone 28, as well as other suitable wireless device structures.
The antenna structure 230 includes the printed FM antenna 70 and the battery 226 in a spaced-apart relation via a dielectric spacer 257. The dielectric spacer 257 includes a first dielectric spacer portion 260 and a second dielectric spacer portion 262. The dielectric spacer 257 also includes web portions 261 that space the first and dielectric spacer portion 260 and 262 in a fixed relation, providing a first side 263 and a second side 265. The dielectric spacer 257 provides further separation between the battery 226 and the printed FM antenna 70, which services to improve the E-M flux characteristics of the printed FM antenna, and improves the performance of the printed FM antenna 70.
The dielectric spacer 257 has different dielectric constants that are attributed to the components of the dielectric spacer 257 and the cavity 259 defined therein, which may be “filled” with air from the surrounding environment. Also, the dielectric space 257 may be formed of a similar material throughout, or formed with multiple materials with different dielectric properties.
In this manner, the dielectric spacer 257 provides electrical insulation between the printed FM antenna 70 and mobile phone components, while also supporting electrostatic fields. In general, the area of the dielectric spacer 257 substantially corresponds to the surface area of the printed FM antenna 70; however, dielectric spacers with smaller surface areas may also be used while the desired improvement to the performance of the printed antenna 256 is realized.
The printed FM antenna 70 has a planar structure less than a planar area defined by the outer periphery of the battery cover 228, and is positioned adjacent the inner surface of the mobile phone battery cover 228. The battery 226 has a planar surface positioned adjacent the ground plane 224, which may be a conductive outer layer of the battery 226. The conductive outer layer of the battery 226 may partially encase the battery 226 such that the ground plane 224 is positioned between the battery 226 and the printed FM antenna 70. The sandwiched antenna structure 230 provides improved FM signal performance for the printed FM antenna 70.
FIG. 9 is a cross-sectional diagram of the antenna structure 230 of FIG. 8 with the dielectric spacer 257 and a gap 231 between the antenna structure 230 and the battery cover 228.
The antenna structure 230 includes the printed FM antenna 70 and the battery 226 in a spaced-apart relation via the dielectric spacer 257. The printed FM antenna 70 has a planar structure generally corresponding to the dielectric spacer 257 and a conductive layer that provides the ground plane 224. The printed FM antenna 70 has a protective layer 225 and an antenna trace 218, which face adjacent to a first side of the dielectric spacer 257. A conductive layer forming a ground plane 224 is positioned adjacent a second side of the dielectric spacer 257, and the battery 226 is in turn adjacent the ground plane 224.
In this manner, the planar structure of the printed FM antenna 70 and the planar surface of the battery 226 are substantially parallel to each other in a spaced-apart relation, which serves to improve the FM performance of the printed FM antenna 70. Further, the gap 231 provides a further dielectric effect with respect to the antenna structure 230, in that a level of electrical insulation between the antenna structure 231 and the case covers is provided while supporting electrostatic fields conducive to FM antenna operation.
FIG. 10 is a flow diagram of a method 320 of providing an antenna structure to a mobile phone. Beginning at step 322, a dielectric spacer having a first side and a second side is provided to the mobile phone. A printed FM antenna having a planar structure is positioned, at step 324, adjacent the first side of the dielectric spacer. At step 326, a battery having a planar surface is positioned adjacent the second side of the dielectric spacer such that the planar structure of the printed FM antenna and the planar structure of the battery are substantially parallel to each other in a spaced apart relation. At step 328, a conductive material is positioned between the printed FM antenna and the battery to provide a ground plane to the printed FM antenna. The installation of the antenna structure increases the FM performance of the printed antenna, and correspondingly, improves the performance of the wireless communication device in adverse environmental conditions.
As one of average skill in the art will appreciate, the term “substantially” or “approximately”, as may be used herein, provides an industry-accepted tolerance to its corresponding term. Such an industry-accepted tolerance ranges from less than one percent to twenty percent and corresponds to, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and/or thermal noise. As one of average skill in the art will further appreciate, the term “coupled”, as may be used herein, includes direct coupling and indirect coupling via another component, element, circuit, or module where, for indirect coupling, the intervening component, element, circuit, or module does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As one of average skill in the art will also appreciate, inferred coupling (that is, where one element is coupled to another element by inference) includes direct and indirect coupling between two elements in the same manner as “coupled”. As one of average skill in the art will further appreciate, the term “compares favorably”, as may be used herein, indicates that a comparison between two or more elements, items, signals, et cetera, provides a desired relationship. For example, when the desired relationship is that a first signal has a greater magnitude than a second signal, a favorable comparison may be achieved when the magnitude of the first signal is greater than that of the second signal or when the magnitude of the second signal is less than that of the first signal. While the transistors or switches in the above described figure(s) is/are shown as field effect transistors (FETs), as one of ordinary skill in the art will appreciate, the transistors may be implemented using any type of transistor structure including, but not limited to, bipolar, metal oxide semiconductor field effect transistors (MOSFET), N-well transistors, P-well transistors, enhancement mode, depletion mode, and zero voltage threshold (VT) transistors.

Claims

1. A mobile phone with a FM antenna structure having improved performance, the mobile phone comprises:

a printed FM antenna having a planar structure less than a planar area defined by an outer periphery of the mobile phone;

a conductive layer providing a ground plane to the printed FM antenna, the conductive layer adjacent the printed FM antenna in an electrostatic field relation; and

a battery having a planar surface positioned adjacent an opposite side of the conductive layer, wherein the planar structure of the printed FM antenna and the planar surface of the battery are substantially parallel to each other in a spaced-apart relation improving performance of the printed FM antenna.

2. The mobile phone of claim 1 further comprises:

a printed circuit board having integrated circuits including transceiver circuitry coupled to the printed FM antenna, the printed circuit board adjacent the battery.

3. The mobile phone of claim 2 wherein the integrated circuits further comprise:

lumped tuning components dependent upon the relation of the printed FM antenna to the battery, wherein the lumped tuning components define an impedance bringing the printed FM antenna into an operational FM band.

4. The mobile phone of claim 2 wherein the printed FM antenna further comprises:

an input/output connection coupled to the transceiver circuitry.

5. The mobile phone of claim 4 wherein the input/output connection comprises at least one of:

a coaxial probe, a printed microstrip, a waveguide, and a coplanar transmission line.

6. The mobile phone of claim 1 wherein the printed FM antenna comprises at least one of a monopole, a dipole, an eccentric spiral and a fractal antenna.

7. The mobile phone of claim 1 wherein the conductive layer partially encases the battery between the planar structure of the printed FM antenna and the planar surface of the battery.

8. The mobile phone of claim 1 wherein the mobile phone case comprises:

a clamshell structure having a first portion and a second portion coupled by a hinge portion, the first portion including the mobile phone case back cover, the printed FM antenna, the conductive layer, and the battery, the second portion including a display, wherein the first portion and the second portion fold to a substantially parallel position when in a closed position.

9. The mobile phone of claim 1 wherein the printed FM antenna comprises:

an antenna substrate having a dielectric property;

an antenna trace printed onto a planar surface of the antenna substrate; and

a protective layer encapsulating the antenna trace, wherein the planar surface of the antenna substrate having the antenna trace is oriented towards the ground plane.

10. A mobile phone with a FM antenna structure having improved signal-to-noise performance, the mobile phone comprises:

a dielectric spacer having a first side and a second side;

a printed FM antenna having a planar structure positioned adjacent the first side of the dielectric spacer;

a conductive layer providing a ground plane adjacent the second side of the dielectric spacer; and

a battery having a planar surface positioned adjacent the conductive layer, wherein the planar structure of the printed FM antenna and the planar surface of the battery are substantially parallel to each other in a spaced apart relation.

11. The mobile phone of claim 10 further comprises:

12. The mobile phone of claim 11 wherein the integrated circuits further comprise:

13. The mobile phone of claim 11 wherein the printed FM antenna further comprises:

an input/output connection coupled to the transceiver circuitry.

14. The mobile phone of claim 13 wherein the input/output connection comprises at least one of:

15. The mobile phone of claim 10 wherein the printed FM antenna comprises at least one of a monopole, a dipole, an eccentric spiral and a fractal antenna.

16. The mobile phone of claim 10 wherein the conductive layer partially encases the battery.

17. The mobile phone of claim 10 wherein the mobile phone comprises:

a clamshell structure having a first portion and a second portion, the first portion including the printed FM antenna, the conductive layer, the dielectric spacer, and the battery, the second portion including a display, wherein the first portion and the second portion fold to a substantially parallel position when placed in a closed position.

18. The mobile phone of claim 10 wherein the printed FM antenna comprises:

an antenna substrate having a dielectric property;

an antenna trace printed onto a planar surface of the antenna substrate; and

19. A mobile phone with a FM antenna structure having improved FM performance, the mobile phone comprises:

a clamshell structure having a first portion coupled to a second portion, wherein the first portion and the second portion fold to a substantially parallel position when placed in a closed position, wherein the first portion includes:

a printed FM antenna having a planar structure less than a planar area of the mobile phone

a conductive layer providing a ground plane to the printed FM antenna, the conductive adjacent the printed FM antenna in an electrostatic field relation; and

20. The mobile phone of claim 19 wherein the first portion of the clamshell structure further comprises:

21. The mobile phone of claim 20 wherein the integrated circuits further comprise:

22. The mobile phone of claim 19 wherein the printed FM antenna further comprises:

an input/output connection coupled to the transceiver circuitry.

23. The mobile phone of claim 22 wherein the input/output connection comprises at least one of:

24. The mobile phone of claim 19 wherein the printed FM antenna comprises at least one of a monopole, a dipole, an eccentric spiral and a fractal antenna.

25. The mobile phone of claim 19 wherein the conductive layer partially encases the battery.

26. The mobile phone of claim 19 wherein the printed FM antenna comprises:

an antenna substrate having a dielectric property;

an antenna trace printed onto a planar surface of the antenna substrate; and

27. A mobile phone with an FM antenna structure having improved FM performance, the mobile phone comprises:

a dielectric spacer having a first side and a second side;

28. The mobile phone of claim 27 further comprises:

29. The mobile phone of claim 28 wherein the integrated circuits further comprise:

30. The mobile phone of claim 27 wherein the printed FM antenna further comprises:

an input/output connection coupled to the transceiver circuitry.

31. The mobile phone of claim 30 wherein the input/output connection comprises at least one of:

32. The mobile phone of claim 27 wherein the printed FM antenna comprises at least one of a monopole, a dipole, an eccentric spiral and a fractal antenna.

33. A method for providing an antenna structure for a mobile phone, the method comprises:

providing a dielectric spacer having a first side and a second side;

positioning a printed FM antenna having a planar structure adjacent the first side of the dielectric spacer;

positioning a battery having a planar surface adjacent the second side of the dielectric spacer, wherein the planar structure of the printed FM antenna and the planar surface of the battery are substantially parallel to each other in a spaced apart relation; and

positioning a conductive material between the printed FM antenna and the battery to provide a ground plane to the printed FM antenna.

34. The method of claim 33 further comprises:

coupling transceiver circuitry of a printed circuit board having integrated circuits including transceiver circuitry to the printed FM antenna, the printed circuit board adjacent the battery.

35. The method of claim 34 wherein the integrated circuits further comprise:

36. The method of claim 34 wherein the coupling the transceiver circuitry comprises:

coupling an input/output connection of the printed FM antenna to the transceiver circuitry.

37. The method of claim 36 wherein the input/output connection comprises at least one of:

38. The method of claim 33 wherein the printed FM antenna comprises at least one of a monopole, a dipole, an eccentric spiral and a fractal antenna.

39. The mobile phone of claim 33 further comprises:

providing a conductive layer to the battery, wherein the conductive outer layer provides a ground plane to the printed FM antenna.

40. The method of claim 39 wherein the conductive outer layer partially encases the battery.