Patent Application
20070176830
None
Not related to any currently pending patent applications or issued patents.
The present invention relates to antenna for wireless devices and, more particularly, to an antenna capable of receiving digital television signals.
Cellular phones, PDAs, BLACKBERRYs® from Research in Motion, wireless computers, handheld computers and the like are becoming increasingly prevalent in today's society. The uses for such devices include both business uses as well as personal uses. Only a few years ago, wireless devices were relatively limited in use, but today a single wireless device may incorporate features to allow functions such as, for example, cellular communication, internet access, text messaging, credit purchases, bank account access, television viewing, computing, video gaming, navigation information, and the like.
With the increase in consumer use of wireless devices over multiple functions, the need for those devices to operate over multiple radio frequency bandwidths also has increased. Thus, it is not uncommon for wireless devices to incorporate antennas for various frequency bands such as ISM band, Bluetooth band, GPS band, 802.11 band, other cellular bands and the like.
While users of wireless devices are demanding that wireless devices be more versatile and perform more functions, they are concurrently demanding that the wireless devices become lighter, smaller, and generally more compact. Decreasing the size of the wireless device while increasing the number of functions is increasingly difficult. Moreover, to accommodate the increase in electronic components, the manufacturers are increasingly restricting the space available for radio frequency antennas. Thus, it would be desirous to develop improved antennas for one or more of the various wireless functions associated with today's wireless devices.
To attain the advantages of and in accordance with the purpose of the present invention, a planar antenna for a foldable wireless device is provided. The foldable wireless device and antenna include a first housing and a second housing pivotally connected. A ground plane, which may be a printed circuit board, associated with the wireless device comprises a first ground plane in the first housing and a second ground plane in the second housing. The first and second ground plane function as first and second radiating plates respectively. A gap, generally aligned with the pivotal connection separates the first and second ground planes. A short is provided that traverses the gap and connects the first and second ground planes.
The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.
The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
The improved antenna for a flip style wireless device will be described with references to the figures. For convenience the antenna is shown and described in relation to a flip style cellular telephone. However, one of ordinary skill in the art on reading the disclosure will now recognize that alternative flip style wireless devices could benefit from the antenna described. Other wireless devices include, for example, laptop computers, portable televisions, PDAs, BLACKBERRYs®, handheld computers, pagers, and the like.
Referring first to
Referring now to
In most instances, the antenna transmits and receives simultaneously. In an embodiment of the present device, the antenna receives only. Radio frequency power is supplied or received through a power feed 214 to first PCB 202 at power point 216 on first edge 208 and to second PCB 204 at power point 218 on second edge 208. A wire 217 connects power point 216 and power point 218. Power feed 214 could be any number of radio frequency power transmission structures, such as, for example, a microstrip line, a coaxial cable (as shown), a solder connection, a conductive strip on a circuit board or the like.
Wire 217 connects the two power points and functions as the center conductor of a transmission line formed by edges 208 and 210. The transmission line formed by edges wire 217, edge 208, and edge 210 also forms a portion of the radiator in addition to transforming the impedance between power points 216 and 218. Without wire 217, a short forms at lower operating frequencies between edges 208 and 210, which inhibits operation at lower frequency bands.
RF power may be supplied to power points 216 and 218 by any conventional power source 220 located on first PCB 202. Conventional power source 220 may include signal generators, amplifiers, and modulators. However, as the device can be receive only, the power source is optional.
Radiator 200 can be tuned to particular operating frequencies by varying a length L and width W of the first and second PCBs 202 and 204 as well as increasing or decreasing the size D of gap 206. Moreover, altering a length of wire 217 can be used to tune radiator 200. Moreover, each PCB could have one or more slots (such as slot 222 shown in phantom on PCB 204) to quasi-partition the PCB, but such slots are optional and likely not necessary. While first PCB 202 and second PCB 204 are shown having identical lengths L and widths W, the lengths and widths of each part may vary.
Digital television signals conventionally operate at relatively low frequencies such as 440 MHz to 470 MHz. Radiator 200 is especially useful in receiving digital television signals. For example, if wireless device 100 were a flip cellular phone, a PCB ground plane 200, which coincides with the radiator, becomes a linear inverted-F antenna with a very tall radiating element in nearly the same plane as the ground plane. The above design, while useful in many applications, is especially useful for reception of the low frequency digital television signals. The device can also be configured to operate at the higher digital TV frequencies in the L-band near 1300 MHz.
While useful for receiving digital television signals, the low frequency of the signals and the size of the radiator may require the use of a matching network 224. While any conventional matching network is possible, matching network 224 is shown and includes a varactor diode.
While the antenna has been particularly shown and described with reference to an embodiment thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made without departing from the spirit and scope described herein.
