The present disclosure relates generally to methods and systems related to radio frequency (RF) communication devices.
In emerging markets throughout the world, such as China and India, the rising middle and lower-middle classes are demanding affordable wireless service. To tap this huge market, wireless service providers are striving to provide affordable access services and handsets to these customers.
Consequently, engineers are continuously looking for ways to modify existing mobile phone architectures to achieve a lower cost design without giving up quality or desirable features.
The following presents a simplified summary. This summary is not an extensive overview, and is not intended to identify key or critical elements. Rather, the primary purpose of the summary is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
One embodiment relates to a circuit for efficient wireless communication. The circuit includes an antenna feed and a plurality of communication paths stemming from the antenna feed, where different communication paths are associated with different frequency bands. The circuit also includes a shunt coupled to the antenna feed and adapted to selectively divert power from the antenna feed as a function of shunt control signal.
The following description and annexed drawings set forth in detail certain illustrative aspects and implementations. These are indicative of only a few of the various ways in which the principles disclosed may be employed.
One or more implementations will now be described with reference to the attached drawings, wherein like reference numerals are used to refer to like elements throughout. It will be appreciated that nothing in this specification is admitted as prior art.
To limit the transmit power that reaches the reception phase shift selection circuits, the inventors have fashioned wireless communication devices that include transmission and reception shunts. During operation, these transmission and reception shunts selectively divert power from the reception feed and/or transmission feed, thereby isolating the transmission and reception feeds.
During operation, the communication device 300 is assigned to its own transmission time slot 402 and its own reception time slot 404 within a frame (
In this manner, the shunts 302, 304 isolate the transmission feed 314 and reception feed 316 from one another. In addition, capacitors 315, 317, 319, 321 may also be present along the transmission and reception feeds 314, 316, where the capacitors are on opposing sides of the shunts. Moreover, as described in more detail below, individual communication paths that stem from the communication feeds 314, 316 are also isolated from one another by the use of phase shift selection circuits.
On the transmit side, a first transmission path 322 and a second transmission path 324 stem from the transmission feed 314 and deliver different respective frequency components to the transmission feed. The first and second transmission paths 322, 324 include first and second transmission phase shift selection circuits 326, 328 and first and second power amplifiers 330, 332, respectively.
On the receive-side, a first reception path 334 and a second reception path 336 stem from the reception feed 316 and separate out (filter) different respective frequency components from the reception feed. The first and second reception paths 334, 336 include first and second reception phase shift selection circuits 338, 340 and first and second low noise amplifiers 342, 344, respectively.
During transmission, the transmitted signal RFT, which is provided to the dual feed antenna 346 via the transmission feed 314, can include frequency components falling within one of two transmission frequency bands. The first transmission path 322 provides a transmission signal over a first transmission frequency band, while the second transmission path 324 provides a transmission signal on a second transmission frequency band.
For example, when the signal generator 348 generates an outgoing signal RFO1 in the first transmission frequency band (e.g., ˜880-915 MHz), the first transmission phase shift selection circuit 326 is structured to represent an approximately matched impedance (e.g., about 50 ohms). Consequently, the first power amplifier 330 amplifies RFO1 to generate an amplified signal RFA1. For RFA1, the first transmission phase shift selection circuit 326 passes frequency components within the first transmission band with limited or no attenuation and suppresses the high frequency components generated by the first power amplifier 330. The second transmission phase shift selection circuit 328 is structured to represent a high or infinite impedance for the first transmission frequency band. Consequently, although RFA1 passes through the first transmission phase shift selection circuit 326, it will not leak through the second transmission phase shift selection circuit 328 and a vast majority of the power in RFA1 will be successfully transmitted to the dual feed antenna 346.
Conversely, in the second transmission frequency band (e.g., 1710-1785 MHz), the signal generator 348 generates an outgoing signal RFO2 on the second transmission path 324. The second power amplifier 332 then amplifies or modulates the signal RFO2, thereby generating an amplified signal RFA2 that is passed to the second transmission phase shift selection circuit 328. Because the second transmission phase shift selection circuit 328 represents a matched impedance at the second transmission frequency band, RFA2 passes through with limited or no attenuation. The transmission phase shift selection circuit 328 will suppress other high frequency components generated by the second power amplifier 332. The frequency components passing through the second transmission phase shift selection circuit 328 will see a high impedance at the first transmission phase shift selection circuit 326, so power will not leak back through the first transmission phase shift selection circuit 326. In this way, the transmission frequency bands are isolation from one another.
The received signal RFR, which is provided to the reception feed 316 from the dual feed antenna 346, can include practically any frequency component detected by the dual feed antenna 346. Therefore, the first reception path 334 separates out signal components within a first reception frequency band (e.g., about 925-960 MHz), while the second reception path 336 separates out signal components within a second reception frequency band (e.g., about 1805-1880 MHz). Consequently, only RFF1 passes through the first reception phase shift selection circuit 338 with limited or no attenuation. Conversely, only RFF2 passes through the second reception phase shift selection circuit 340 with limited or no attenuation. These filtered signals RFF1, RFF2 are then amplified by low noise amplifiers 342, 344 to generate incoming signals RFI1, RFI2. The incoming signals are then demodulated and analyzed by the demodulator and signal analyzer 350, which can pass analyzed signals to a user interface (e.g., speaker, visual display, etc.).
Although the illustrated embodiment shows a dual-feed antenna 346 where two transmission paths 322, 324 and two reception paths 334, 336 stem from the respective communication feeds, in other embodiments more than two transmission paths could stem from the transmission feed 314 and more than two reception paths could stem from the reception feed 316. For example, in one embodiment of a quad-band phone, four transmission paths could stem from the transmission feed 314, and four reception paths could stem from the reception feed 316. In one embodiment, the dual-feed antenna 346 could be a planar inverted F antenna (PIFA), but could also be other types of antennas in other embodiments.
As shown in
In
In some embodiments, the power supply capacity of each SAW filter 318, 320 is about 15 dBm, whereas a transmit power of about 35 dBm can be presented at the transmission feed 314. As a result, about 20 dB of isolation between the transmission feed 314 and reception feed 316 may be desirable.
This will prevent damage to the SAW filters 318, 320 and will prevent performance degradation due to too much power at the LNA input ports.
Now that some examples of systems have been discussed, reference is made to
At 902, the wireless communication device identifies the start of frame N. At 904, the wireless communication device identifies a time slot M within the frame N.
At 906, a determination is made whether the time slot M is a transmit slot that is reserved for the wireless communication device. If so (“YES”) at 906, a signal RFT is transmitted over an antenna via a transmission feed. During transmission during time slot M, power is concurrently shunted from the reception feed of the antenna.
If the time slot M is not a transmission slot for the wireless communication device (“NO” at 906), the method proceeds to 910. In 910, a determination is made whether the time slot M is a receive slot reserved for the wireless communication device. If so (“YES” at 910), the method proceeds to 912, and an signal RFR is received over the receive feed. While the signal RFR is received during timeslot M, power is concurrently shunted from the transmission feed to incorporate a symmetrical antenna design with the transmission mode. In this way, isolation is achieved between the transmission feed and reception feed.
After time slot M is carried out, the method can evaluate other timeslots and other frames in a similar manner (e.g., 914).
Although one or more implementations has been illustrated and/or discussed above, alterations and/or modifications may be made to these examples without departing from the spirit and scope of the appended claims. For example, although some embodiments describe a wireless communication device as a cellular phone, in other embodiments the wireless communication device could be another type of communication device, including but not limited to: a personal digital assistant, a pager, a walkie-talkie, a music device, a laptop, etc.
Some methods and corresponding features of the present disclosure can be performed by hardware modules, software routines, or a combination of hardware and software. To the extent that software is employed, for example by a baseband processor or other processor associated with the radar system, the software may be provided via a “computer readable medium”, which includes any medium that participates in providing instructions to the processor. Such a computer readable medium may take numerous forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical disks (such as CDs, DVDs, etc.) or magnetic disks (such as floppy disks, tapes, etc.). Volatile media includes dynamic memory, such as ferroelectric memory, SRAM, or DRAM. Transmission media includes coaxial cables, copper wire, fiber optics, etc. that could deliver the instructions over a network or between communication devices. Transmission media can also include electromagnetic waves, such as a voltage wave, light wave, or radio wave.
In particular regard to the various functions performed by the above described components or structures (assemblies, devices, circuits, systems, etc.), the terms (including a reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated, to any component or structure which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms “including”, “includes”, “having”, “has”, “with”, or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising”.