Multiband conformed folded dipole antenna

A multiband comformed-slotted-folded dipole antenna (200) having a unitary conformed shape conductor conforming to an internal communication device configuration (400). The antenna can include a folded dipole (203, 205, 209, 206, 204) forming a part of the unitary conformed shape and having a first portion (212 or 213) forming at least one slot in a slotted plane (220) and a second portion (210 or 211) forming at least one slot in a second plane (230) substantially perpendicular to the slotted plane. The at least one slot in the second plane controls high band antenna resonance and a length (209) of a metal portion in the slotted plane controls lower band resonance. Additional embodiments are disclosed.

FIELD OF THE DISCLOSURE

This invention relates generally to antennas, and more particularly to a multiband antenna operating on several distinct bands.

BACKGROUND

As wireless devices become exceedingly slimmer and greater demands are made for antennas operating on a diverse number of frequency bands, common antennas such as a Planar Inverted “F” Antenna (PIFA) design becomes impractical for multiband use in such slim devices due to its inherent height requirements. Antenna configurations typically used for certain bands can easily interfere or couple with other antenna configurations used for other bands. Thus, designing antennas for operation across a number of diverse bands each band having a sufficient bandwidth of operation becomes a feat in artistry as well as utility, particularly when such arrangements must meet the volume requirements of today's smaller communication devices.

DETAILED DESCRIPTION

FIG. 1depicts an exemplary embodiment of a communication device100. The communication device100comprises an antenna102, coupled to a communication circuit embodied as a transceiver104, and a controller106. The transceiver104utilizes technology for exchanging radio signals with a radio tower or base station of a wireless communication system according to common modulation and demodulation techniques. Such techniques can include, but is not limited to GSM, TDMA, CDMA, UMTS, WiMAX, WLAN among others. The controller106utilizes computing technology such as a microprocessor and/or a digital signal processor with associated storage technology (such as RAM, ROM, DRAM, or Flash) for processing signals exchanged with the transceiver104and for controlling general operations of the communication device100.

One embodiment of the present disclosure can entail a multiband comformed-slotted-folded dipole antenna having a unitary conformed shape conductor conforming to an internal communication device configuration, a folded dipole forming a part of the unitary conformed shape and having a first portion forming at least one slot in a slotted plane and a second portion forming at least one slot in a second plane substantially perpendicular to the slotted plane. The antenna can have at least one slot in the second plane controls high band antenna resonance and a length of a metal portion in the slotted plane controls lower band resonance. Note that the unitary conformed shape conductor is a single or contiguous conductor shaped to conform to a particular structure that can include one or more elements. For example, the unitary conformed shape conductor can conform to the shape of a circuit board and a speaker on the circuit board. The unitary conformed shape conductor can also conform to the circuit board itself or with other components as desired.

Another embodiment of the present disclosure can entail an antenna having a conformed slotted dipole antenna element having first antenna elements in a slotted plane and second antenna elements in a second plane, wherein the slotted plane is substantially orthogonal to the second plane, a first slot and a second slot in the second plane that controls a high band resonance when the slots are tuned, and a conductive line in the slotted plane having a length that controls a low band resonance.

Yet another embodiment of the present disclosure can entail an antenna having a substantially T-shaped slot in a slotted plane forming a low band controlling line portion coplanar and above the T-shaped slot and a high band controlling line portion coplanar and below a cross bar of the T-shaped slot, and a conductive line that is non-coplanar with the slotted plane and forms a slot having a gap between the slotted plane and the conductive line, wherein the gap further controls a high band resonance of the antenna.

Yet another embodiment of the present disclosure can entail a communication device comprising an antenna, a communication circuit coupled to the antenna, and a controller programmed to cause the communication circuit to process signals associated with a wireless communication system.

Antenna design for mobile devices (such as cell phones and PDAs) are facing additional challenges due to devices getting smaller and packed with electronic parts having more features. Therefore the volume for antennas is limited but requirements for antenna performance still remain reasonable high. Furthermore, technologies or new functions require multi-band operations of devices. To deal with these requirements and limitations, antenna engineers have come up with a lot of innovative designs such as (folded J antenna) FJA, (folded inverted conformed antenna) FICA, and (folded dipole antenna) FDA. Unfortunately, some of drawbacks or limitations exist when these antennas are applied to mobile devices.

In current implementations, an FJA requires at least 13 mm of space away from any grounded plane (such as a printed circuit board (PCB)). Sometimes there is difficulty in tuning antenna bands when interaction exists between two arms (in the cases that two arms are overlapped with certain separation).

FICA and FDA are not sensitive to a grounded plane and can provide some level of immunity to the human body (torso, head, or hand) due to the design of the grounded end. Nonetheless, it is very hard for a FICA design to be tuned for different bands because the bands share the same antenna elements. Every tuning for one band will affect other bands hence the tuning process is time-consuming due to the lack of independence of the antenna elements.

For FDAs (simple loop-like), besides the main resonance (2/λ or 4/λ resonance), other desired resonant bands are generally difficult to obtain, or if they are tuned, it is difficult to tune those bands without significantly impacting the main resonance (same issue discussed above with respect to a FICA design).

To mitigate or overcome the drawbacks described above, a new antenna was designed for a mobile device with multi-band operations. The design is a conformed, slotted, and folded antenna. In the design, beside a dipole structure for low band 800 MHz and 900 MHz, a special slot technique is applied to create any desired resonance such as GPS, 1800/900 band, or 2.4/2.5 GHz, and so on which can be independently tuned by bands that correspond to particular structures in the new design or designs. It is a good technology-combined design. In its structure and concept, the design can be referred to as a Conformed-Slotted-Folded Dipole (CSFD).

The CSFD antenna can create a desired resonance easily and the tuning for different bands is very simple. The grounded end of the antenna provides itself with the advantage of being less sensitive to a human body as in FICA and FDA designs.

FIG. 2depicts a top perspective view of a conformed slotted folded dipole antenna200andFIG. 3depicts a bottom perspective view of the same antenna200. The antenna200can include a feeding end or feed201(hot launch) and a grounded end202(cold launch) which can be reversed. Low band resonance can be created by elements203,205,204,206, and209. This combination of elements forms a folded dipole where the tuning for this low band can be realized by tuning or trimming element209which can be a longer straight line or meandering if space is limited.

Resonances in other bands (such as high bands) can be created from slots created from elements207and208along with elements203,205,204, and206which in combination forms slots210,211and214. Tuning these bands can be carried out easily by simply cutting (or adding) conductive portions or metal pieces from (or to) elements207and208(i.e., change the length of slots A and B). Slots A and B should be symmetric for easy band-tuning. But asymmetric slot tuning can also be applied, depending on the bands required.

Tuning low band and high bands are primarily or totally independent because low band tuning relies on the total length of the elements but high band tuning relies on the slots A and B. During each tuning, the common elements203,205,204, and206do not need to change, which, combined with the slot concept, facilitates creation of other bands and the ability to tune all the bands easily and independently.

In the embodiments herein, during the tuning of high bands, the change of slots212and213has little effect on low band resonance with respect to antenna element209. This is an additional verification that high bands are mainly created by slots A (210) and B (211).

The separation of the gaps of slots A and B can be used to tune its resonance as well. The wider the gaps (210,211, and/or214), the higher the frequency moves to. It is found that this tuning method for high bands only brings a very little (or insignificant) effect on low band resonance because elements205and206are changed but they are very small segments compared to the total length of the folded dipole antenna for low band resonance. Plots for different slot tunings in the design of antenna200can illustrate that resonance in high bands moves drastically with tuning but the low bands (such as the 850 and 900 MHz bands) see a very small change.

As noted above, one embodiment can entail a multiband comformed-slotted-folded dipole antenna having a unitary conformed shape conductor (200) conforming to an internal communication device configuration (see400ofFIG. 4), a folded dipole (203,205,209,204, and206) forming a part of the unitary conformed shape and having a first portion (212,213and/or214) forming at least one slot in a slotted plane220and a second portion (210or211) forming at least one slot in a second plane230substantially perpendicular or orthogonal to the slotted plane220. The antenna can have at least one slot in the second plane that controls high band antenna resonance and a length of a metal portion209in the slotted plane220that controls lower band resonance.

Another embodiment can more particularly include a first slot A or210and a second slot B or211in the second plane230that controls a high band resonance when the slots are tuned, and a conductive line209in the slotted plane having a length that controls a low band resonance.

Yet another embodiment of the present disclosure can entail an antenna200having a substantially T-shaped slot (form by slots212,213, and214) in a slotted plane220forming a low band controlling line portion209coplanar and above the T-shaped slot and a high band controlling line portion (207and/or208) coplanar and below a cross bar of the T-shaped slot, and a conductive line (203and/or204) that is non-coplanar with the slotted plane220and forms a slot having a gap (210and/or211) between the slotted plane220and the conductive line203,204where the gap further controls a high band resonance of the antenna.

Besides the easier multi-band resonance creation and tuning, the embodiments herein can conform to the various shapes or components that might be found in today's diverse communication devices. For example, as illustrated inFIG. 4, the antenna200can conform to the top of an audio transducer or speaker406for a communication device400. In one particular embodiment, the antenna200can be placed only 2.5 mm away from the magnetic and metal parts of the speakers406and hence advantageously use the volume in the phone. The design also relaxes the “keep-out” distances that the antenna must have from a PCB grounded plane. Communication device400can include a printed circuit board (PCB)404that has a grounded plane that can include shields404. In a FJA design, the antenna should be at least 13 mm away from the ground plane, but a design in accordance with the embodiments herein can have the antenna just 4.5 mm away from the PCB ground plane.

Note that the antenna200can also provide a wide resonance at low band. Obtaining such a wide resonance at low bands can be particularly difficult for flip phone configurations, but the embodiments herein are suitable for flip phones and monolith shaped devices where the wide resonance can be moved to a desired low band based on a given length of a phone for example. Further note that since the antenna's volume can be large, the bandwidth of antenna will improve. Also, as in FICA and FDA designs, the grounded end of the CSFD antenna helps reduce the adverse effect from proximity to human body parts (torso, head, hand) and thus it can provide for good performance in real use cases.

The foregoing embodiments of the antennas illustrated herein provide a multiband antenna design with a wide operating bandwidth where desired. Application of this design can be for any wireless devices, not necessarily limited to mobile devices.