WO2008149351A2

WO2008149351A2 - Electronically steerable antenna system for low power consumption

Info

Publication number: WO2008149351A2
Application number: PCT/IL2008/000753
Authority: WO
Inventors: Gil Levi; Gil Meyuhas; Alexander Toshev
Original assignee: Bon Networks Inc.
Priority date: 2007-06-04
Filing date: 2008-06-04
Publication date: 2008-12-11
Also published as: WO2008149351A3

Abstract

An electrically steerable directional antenna (ESDA) system in which antenna elements transmit and receive signals with phases obtained from a phase bank. The phases are controlled by an antenna controller. Some or all of the phases may be different. In some embodiments, the phase bank includes delay lines having respective lengths. Each delay line imposes a phase delay relative to its length on a signal passing therethrough. Some or all the components of the antenna system may be implemented in a semiconductor chip. The ESDA is steerable by changing the phases of the signals routed to each of the antenna elements from time to time.

Description

ELECTRONICALLY STEERABLE ANTENNA SYSTEM FOR LOW POWER CONSUMPTION

FIELD OF THE INVENTION

The invention relates generally to antennas and more particularly to electrically steerable directional antennas (ESDAs) or phased array antennas (PAAs). In the following description, ESDA and PAA are used interchangeably.

BACKGROUND OF THE INVENTION

Electrically (or electronically) steerable directional antennas are known in the art and are usually used in radar and other military systems. These systems use a set of radiating antenna elements (or simply "antenna elements"), each driven by a radio frequency (RF) signal via a phase shifter. The antenna beam can be steered to the appropriate direction through the control of the phase of the RF signal supplied to each such element. ESDAs are usually large (not suitable for handheld devices) and quite expensive due to the cost of their components. An antenna controller is needed to control and track the directional antenna. The controller can acquire the correct direction at start of transmission or reception and can track the communication direction in real time to sustain a working RF link between communicating entities. Such tracking is particularly needed in handheld devices communicating with a base station or cell. The algorithms needed to track the direction of the base station or cell must also be matched with the communications protocol being used and therefore the antenna control mechanism usually requires integration with a baseband modem at the medium access control (MAC) and physical (PHY) layers. Due to such limitations, it has been impractical to integrate ESDA technology into wireless systems such as mobile phones and Personal Digital Assistants (PDA's). Nevertheless, there is a need for and it would be advantageous to have such integration of ESDAs in such systems. SUMMARY OF THE INVENTION

An ESDA system of the invention includes a PAA operable by signals at different phases (or "phase states") applied to its antenna elements. The different phases are obtained from a phase bank, hi some embodiments, the phase bank includes delay lines having respective lengths. Each delay line imposes a phase delay (phase shift) relative to its length on a signal passing therethrough. Different length delay lines therefore impose different phase shifts. The phase bank thus incorporates "sets" of phases ("phase sets") used to drive the ESDA. The phases in a set are measured relatively to each other in order to determine a "delta" phase shift of each phase in the bank relative to the other phases.

In a transmit path, a same-phase signal split into n signals by a 1 : n splitter enters the phase bank where the n signals are phase-shifted, thereby exiting the phase bank with potentially different phases. Conversely, in a receive path, n signals entering the phase bank with potentially different phases are phase shifted to have a similar phase when they exit the phase bank. The similarly phased signals are then combined into a single RF signal by a n: 1 combiner. The phase shifts are relative between the n signals. From time to time, the antenna beam can be changed (steered) by switching the phase sets to the antenna elements. This allows for multiple configurations of phases to be provided to the antenna elements.

In some embodiments, the entire ESDA system may be implemented in a single semiconductor die (or "chip"). In other embodiments, the entire ESDA system except the antenna elements may be implemented in a single semiconductor chip. In yet other embodiments, the entire ESDA system except the antenna elements and the phase bank may be implemented in a single semiconductor chip.

In some embodiments, a single semiconductor chip may be used with many different delay lines to control and drive many antennas, hi some embodiments, the same delay lines may be used with a large number of antennas by using multiple semiconductor chips for drive and control. In some embodiments, different sets of delay lines, which comprise the respective phase bank, may be used with a large number of antennas by using multiple identical semiconductor dies for drive and control.

In some embodiments, there is provided an ESDA system which includes n antenna elements, wherein n is equal to or greater than 4; a phase bank with at least n phase lines for associating respective phase states with respective signals passing therethrough; a 1: n splitter for splitting a transmit RF signal into n signals; a n:l combiner for combining n signals into a receive RF signal; a switching network for electrical coupling between the antenna elements, the phase bank, the splitter and the combiner; and an antenna controller for controlling the ESDA system.

In some embodiments, the ESDA system may be coupled to a monitoring subsystem that includes a detection switch, a tunable filter and a detector, all of which serve for internal measurements that provide inputs to the antenna controller. In some embodiments, there is provided a method for implementing an ESDA including the steps of: providing a plurality of antenna elements; applying a signal with a respective phase to each element, each respective phase formed in a phase bank coupled to the phased array antenna; and forming and steering a directional antenna beam using the signals with respective phases. In some embodiments, there is provided a method for implementing an ESDA comprising the steps of: providing n antenna elements, wherein n is at least 4; in a transmit path, using a phase bank to phase-shift respective phases of at least some of n signals passing therethrough to provide at least some exiting signals having potentially different phases, and applying the exiting signals to respective antenna elements to obtain a directional beam of a transmit signal; and, in a receive path, using a phase bank to phase-shift respective phases of each of n signals passing therethrough to provide n exiting signals having identical or similar phases, and combining the identical or similar phase signals into a single receive signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: FIG. 1 shows a block diagram of one embodiment of ESDA system;

FIG. 2 shows a block diagram of another embodiment of an ESDA system; FIG. 3 shows a block diagram of yet another embodiment of an ESDA system which includes a power amplifier (PA) and a low noise amplifier (LNA);

FIG. 4 shows an exemplary diagram of a transmit phase bank; FIG. 5 shows an exemplary diagram of a switching network;

FIG. 6 shows a block diagram of another embodiment of an ESDA system using a partitioning which allows implementation of the system on a semiconductor die;

FIG. 7 shows a block diagram of another embodiment of an ESDA system implemented on a semiconductor chip with external antennas;

FIG. 8 shows a block diagram of a multiple chip embodiment of a larger antenna array.

In the following description like elements in different figures are marked with identical numbers.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows one embodiment of an ESDA system 100 implemented exemplarily using a four antenna element PAA. Note that the number of antenna elements may in general be any number "n" equal to or greater than 4. System 100 includes a transmit side 101a with a 1:4 (or in general 1 : n) splitter 102, a transmit phase bank 104, a transmit switching network 106 and four transmit antenna elements 108 (1-4); a receive side 101b with four receive antenna elements 110 (1-4), a 4:1 (or in general n:l) combiner 112, a receive phase bank 114, a receive switching network 116 and an antenna controller 124, interconnected as shown.

In some embodiments, system 100 may optionally also include a monitoring subsystem that includes a detection switch 118, a tunable filter 120 and a detector 122. When included, the monitoring subsystem serves for internal measurements that provide inputs to the antenna control. Alternatively, in some embodiments, these measurements may be performed by a monitoring subsystem external to system 100.

In operation, on the transmit side, a transmit RF signal enters splitter 102, which separates the signal into four separate signals with identical phase, each of which enters transmit switching network 106, which directs each of the signals into a correct entrance in transmit phase bank 104. A phase bank of the invention is actually a set of multiple input-output port pairs, with each pair causing the entering signal a similar or different phase shift between the input point and the output point. This essentially returns the four separate signals back into the transmit switching network, each at a desired phase. The switching network then routes the signals, each with its phase state, into the appropriate antenna element 108 to form the desired PAA signal. The PAA signal is then transmitted wirelessly by the antenna to the desired direction. The beam direction of the PAA is controlled by the different phase assignment of the signals to the antenna elements. On the receive path, the four receive antenna elements 110 receive RP signals and pass them to receive switching network 116. Network 116 (as 106 in the transmit path) directs each signal into an appropriate entrance of receive phase bank 114. From the phase bank, the four separate signals are returned, each at a potentially different phase, back to receive switching network 116, according to the desired direction of the antenna beam. The four separate RF signals are then routed into combiner 112, which, after combining the four signals into a single receive RF signal, directs the receive RF signal into detection switch 118. This switch is then controlled to either route the signal into the RF receiver to be interpreted as needed (most often), or alternatively, as part of a tracking and acquisition (or simply "tracking") algorithm which decides the optimal beam, to pass the signal or part of it through tunable filter 120. The filter selects the correct frequencies or other attributes to be monitored according to the service type, service provider, supported channels, etc. The filtered signal is then passed into detector 122, which is able to determine the quality and strength of the signal as part of the tracking algorithm of ESDA system 100. The entire antenna system is controlled and optionally monitored via antenna controller 124. The tracking algorithm is an appropriate applied method to scan all beams during operation and to decide which beam is the optimal beam to be used, typically according to a comparison of measurement done using the different beams of the antenna. The main functionality of antenna controller 124 is to acquire and track the signal (usually the transmissions between the handset and the base stations) and to determine the optimal direction of the antenna beam for best transmission and reception at all times. When monitoring, the controller selects the beam to be monitored, reads the measured performance of the beam and records it in order to compare the results of all beams and to select the optimal beam to be used. This is done either periodically or continuously, using either algorithms and modes listed below or other algorithms known in the art. A main purpose of the tracking algorithms is to ensure that at all times the antenna beam is directed in the optimal direction for the best performance of the handset transmission and reception.

The phase sets needed to drive the antenna elements are computed according to the particular requirements of an application. These requirements may include (but are not limited to) frequencies, gains, coverage, physical dimensions and phase sets. For example, a set of particular phases with a phase shift of 0°, 90 , 180° and 270° may be applied to the four antenna elements 110 to obtain an essentially omnidirectional PAA beam, similar to that in FIG. 2a and 2b of co-pending PCT application PCT IL08/000636, which is incorporated herein by reference in its entirety. However, in contrast with application PCT/IL08/000636, the phases herein are obtained through a phase bank instead of from outputs of differential amplifiers or filters. Other phase sets which provide directional beams may be applied, and the exemplary phase above in not limiting in any sense.

Tracking algorithms are known in the art and appropriate ones may be used. One exemplary algorithm involves measuring the power of the received signal from each antenna beam at the appropriate frequency and selecting the highest power beam measured to be used at all times. The use of tracking algorithms, specifically the time used and the selection of the antenna beams to be tested at these times to allow for optimal coverage of all directions, can be done according to various modes. The following exemplary embodiments of tracking and acquisition modes can be used to control the ESDA beam directions. T/R switch mode: In this mode, the tracking of the system is done every time a switch command is passed to the transmit and receive (T/R) switch in a typical wireless system. This type of system is usually referred to as a TDD (Time Division Duplex) system or half duplex system. Since a typical switching time for widely available T/R switches is at most around a few micro seconds (μs), system 100 or a simplified system 200 (FIG. 2) which also integrates the functionality of the T/R switch, can complete the tracking algorithm that checks the different beams and then switch from transmit to receive or from receive to transmit at typical T/R switching times of a few μs. Each time a T/R switch command is issued to the system, the tracking algorithm switches the antenna beam according to a selected algorithm, measures the beam performance, and then decides on the optimal beam to be used.

• Timer mode: hi this mode, at every specified interval, which is configurable according to application and wanted performance, the tracking algorithm switches the antenna beam according to a selected order, measures the beam performance, and then decides on the optimal beam to be used according to the measurements.

• Idle mode: In this mode, the system acts similarly to the above timer mode, only the trigger to begin the tracking algorithms is when the handset signals that it is in idle state and the proposed system can then switch the antenna to measure the beams and decide upon the optimal beam to be used from the measurement results.

Other modes and algorithms may also be used and the proposed system is not limited to the modes and algorithms specified above.

In order to minimize the size, complexity and costs of system 100, it is possible to combine functionalities to simplify the antenna system and reduce the number of components. An exemplary embodiment of such a simplified system is shown in FIG. 2.

FIG. 2 shows a block diagram of a simplified ESDA system 200 implemented exemplarily using a four antenna element PAA. As in system 100, the number of antenna elements n may be in general any number equal to or greater than 4. System 200 is similar to system 100, except that a single phase bank 204 now provides the functionalities of the separate phase banks 104 and 114 of FIG. 1, and a single switching network 208 now provides the functionalities of the separate transmit and receive switching networks 106 and 116. A 1 : 4 (or in general 1: n) splitter 202, a 4:1 (or in general n: 1) combiner 210 and an antenna controller 216 are now coupled to switching network 208. Also, four antenna elements 206 are now used for both transmission and reception. Each antenna element 206 includes a T/R switch 220 and an antenna 222. Similarly to system 100, system 200 may optionally include a detection switch 218, a tunable filter 212 and a detector 214. Antenna elements 206 and phase bank 204 are used both by the transmit path and the receive path, though at different times according to the setting of T/R switch 220, which directs its respective antenna 222 either to the receive path or the transmit path.

In operation, on the transmit side, a transmit RF signal enters splitter 202 which separates the signal into four separate signals with identical phases, each of which enters transmit switching network 208, which directs each of the signals into a correct entrance in phase bank 204. The four separate signals are returned into the switching network, each at a similar (to one or more of the others) or different desired phase. The switching network then routes each signal with its appropriate phase into the appropriate antenna element 206, and the PAA signal is then transmitted wirelessly by the antenna to the desired direction.

On the receive path, antenna elements 206 and phase bank 204 are used in a manner similar to the operation in common wireless systems which rely on a T/R switch to switch between modes. This is again typically referred to as "TDD". Elements 206 receive RF signals and pass them to switching network 208. The switching network now directs each of the four signals into the appropriate entrance of phase bank 204, which, after appropriate phase shifting, returns four separate signals back to the switching network 204, each at a potentially different phase, according to the desired direction of the antenna beam. The four separate RF signals are then routed into combiner 210, which, after combining the four signals into a single receive RF signal, directs the receive RF signal into detection switch 218. This switch is then controlled to either route the signal into the RF receiver to be interpreted as needed (at most times), or alternatively, as part of the tracking algorithm which selects the optimal beam, to pass the entire receive signal (or part of the energy of the signal by essentially splitting the signal) to tunable filter 212. The filter selects the correct frequencies or other attributes to be monitored according to the service type, service provider, supported channels, etc. The filtered signal is then passed to detector 214, which is able to determine the signal quality and strength as part of the tracking algorithm of ESDA system 200. The entire antenna system is controlled and optionally monitored via antenna controller 216.

One advantage of system 200 is that it can be implemented in a size small enough to fit in a typical handheld cellular phone. This can be done by printing or stamping antennas 222 on an appropriate material and implementing all other functionalities on a semiconductor die and its chip carrier. That is, the entire system 200 can be fabricated in the same semiconductor die, except for antennas 222 and phase bank 204, which can for example be stamped or printed on an appropriate substrate or a chip carrier. In high frequency systems, where the antenna size is small enough (and proportional to the transmission frequency), antennas 222 may also be incorporated in the semiconductor die. In such systems, the phase bank, in which the phase shifting delay lines (such as 402, 404, 406 and 408 in FIG.4) are also relative in footprint size to the frequency of the transmissions, may also be incorporated in the semiconductor die.

A system disclosed herein may also support multiple-input-multiple-output (MIMO) communications by, for example, combining or using two systems 200. The two systems can be miniaturized into a size small enough to be implemented in handheld cellular phones, such as needed in IEEE 802.16e WiMAX mobile devices. It is also then possible to have separate tracking algorithms and modes for each of the antenna beams of the MIMO system, or an integrated mode which tracks all MIMO beams together, whether at separate times or at the same time. In addition it is also possible to use the system disclosed herein for just one or part of the MIMO system, and use other known in the art antennas for the rest of the MIMO system. Such a scheme may deliver improved MIMO performance due to the enhanced diversity between the different types of antennas. FIG. 3 shows a block diagram of yet another embodiment of an electronically steerable directional antenna system 300. System 300 is similar to system 200, except that it is made "active" by the addition of an integrated RF power amplifier (PA) 302 in the transmit path and of a low noise amplifier (LNA) 304 in the RF receive path. This allows a typical wireless transceiver to connect to antenna system 300 without having to modify the gains and power levels of its RF signal inputs and outputs. The addition of PA 302 and LNA 304 may also be implemented in the same semiconductor die with part or all of system 300, as done in system 200.

FIG. 4 shows an exemplary transmit phase bank (e.g. 104). A receive phase bank has a similar topology. The phase bank shown has four entry points 412 and four exit points 410. Both entry and exit points are marked 1, 2, 3, and 4. A signal that enters one of the entry points must pass through one of four different delay lines 402, 404, 406 or 408. Exemplarily, four signals entering entry points 412 in the same phase state and propagating through different delay lines will exit through exit points 410 with different phase states. These different phase states result from the different lengths of the different delay lines. In general, the delay lines need not all have different lengths. In some embodiments, only some of the delay lines will have different lengths, others having the same length. In other embodiments, each delay line may have a different length. The number "4" of delay lines in FIG. 4 is exemplary. In general, a phase bank may have any number equal to or greater than 4 delay lines or other means (which can alter the phase of a signal by a constant value, unlike phase shifters which change the phase of a signal in a dynamic manner, introducing different shifts from time to time) to provide different phases for signals exiting the bank. In general, there may be more delay lines than antenna elements in the system, such that at any time, some of the delay lines may have signals going through them while others may not be in use. The length of each delay line in the phase bank is preferably determined in the design stage of the PAA to allow the forming of the needed beams.

FIG. 5 shows an exemplary implementation of switching network 208. On the transmit side, the switching network receives from a splitter (e.g. 202 in FIG. 2) four signals of the same phase state into a 4 x 6 switching matrix 502. Each signal is then routed to a desired transmit phase in the phase bank. Transmit signals returning from the phase bank into the switching network enter a 6 x 4 switching matrix 504. Switching matrix 504 then routes each signal to the appropriate antenna element for transmission.

On the receive path the switching network receives four signals from the antenna elements (e. g. 206 in FIG. 2) into a 4 * 5 switching matrix 508. Each signal is then routed to the desired receive phase in the phase bank. Receive signals returning from the phase bank into the switching network enter a 5 x 4 switching matrix 506. Switching matrix 506 then routes each signal to the appropriate entry of a combiner (e.g. 210 in FIG. 2). It is important to notice that the size of the phase bank for the transmit and receive paths may potentially be different.

In cases where the number of phases in the phase bank is equal to the number of antenna elements, the 4 x 6 switching matrix (502) on the transmit path becomes unnecessary and the signals from the splitter may be directly connected to the phase bank. The same applies for the 4 x 5 switching matrix (508) on the receive path, which can be replaced by a direct connection between the antenna elements and the receive phases of the bank. The exemplary phase bank for the switching network described in FIG. 5 needs to be implemented with a total of 22 delay lines. However, in an alternative embodiment, this phase bank may optionally be implemented with 12 delay lines by introducing a series of six 1 x 2 switches (not shown) between matrices 502 and 506 and another series of six 1 ^χ 2 switches (not shown) between matrices 504 and 508. These switches may then choose whether to connect the delay lines to the transmit path or the receive path. This embodiment also allows the delay lines to be shared by the transmit and receive paths if they do not require simultaneous use.

FIG. 6 shows a block diagram of another embodiment of an electronically steerable directional antenna system which is partitioned to allow implementation of the system on a semiconductor die. In this embodiment, system 300 is split into three sections: a section including only the antennas (222), a section including only the phase bank (204) and a section 600 representing the rest of the system. This partitioning is beneficial when implementing system 300 for low cost applications since this implementation allows the reuse of the same semiconductor in multiple antennas without a need to modify section 600. Therefore, using semiconductors for such a system may be done in high volume, thus significantly reducing cost.

FIG. 7 shows a block diagram of another embodiment of an electronically steerable directional antenna system implemented on a semiconductor chip with external antennas. Taking for example system 300, antennas 222 are placed now outside a semiconductor chip 700. The phase bank (204) is printed on the chip carrier as delay lines, and the rest of the system (600) is formed on the semiconductor die. The advantage of this embodiment is that the same semiconductor die (implementing system 600) may be used in different antenna designs and with different phases required in the phase bank. This allows cost reductions from manufacturing the same semiconductor die in large volumes to be used in multiple implementations of a PAA, while still retaining the flexibility to conform to the requirements of all applications.

FIG. 8 shows a block diagram of a multiple chip embodiment of a larger antenna array. In this embodiment, an exemplary PAA is implemented using a semiconductor chip 700. The PAA uses 16 antennas 222. Four semiconductor chips (700, 700', 700" and 700'") are used in parallel to control the 16 antennas by having each chip control four of the antennas. Each of the four chips may use a different phase bank, according to the needs of the specific PAA, but the same semiconductor die (e.g. die implementing system 600) may be used in all four chips. In the transmit path a 1 :4 splitter 802 is used to supply the signals to the four chips. In the receive path, the four signals coming from the four chips are combined using a 4:1 combiner 804.

In summary, the invention addresses the need for power savings in wireless systems in general and in handheld mobile devices, which usually run from battery power, in particular. An ESDA system as disclosed herein adds directivity to the transmissions and receptions of the link of a wireless communication device. This directional antenna reduces interferences and adds a certain gain to the wireless communication system and therefore allows the transmitter to supply a lower powered signal resulting in lower power consumption and therefore a longer working time under battery power. In addition, the increased gain can also be used to extend the link coverage into greater distances between the device and the base station, or improve the quality or the bit rate of the wireless link.

The directional antenna is a PAA in which signals at different phases obtained from a phase bank are applied in a transmit path to the PAA radiating antenna elements to obtain the antenna beam. The phase bank is used to phase shift different signals passing therethrough relatively to one another. The different phases may change in time, allowing steering of the antenna beam. In the receive path, similar phase shifting is performed in the phase bank on signals at different phases received by the radiating antenna elements to obtain same phase signals which are then combined into a single receive signal.

A directional antenna of the invention can be implemented at low cost and in a small footprint. Antennas disclosed herein may be integrated into mobile phones or other small consumer devices such as PDAs, handheld transceivers, cordless phones, wireless mobile phone enhancements such as Bluetooth earpieces, USB and wireless USB accessories, PCMCIA cards, SDIO devices, and other similar devices. These antennas are based on phased array antenna principles, but without the need for a phase shifter in-line with every radiating element.

An ESDA system which can be integrated into the mobile handset can significantly reduce the power consumption and prolong battery life and handset working time per battery charge. Such an antenna system can exemplarily deliver an added 6dB gain vs. typically used handset antennas, and therefore allows an exemplary 75% reduction in the transmission power. This leads to significant overall power savings, since the RF transmitter is one of the largest power consuming modules in the handset.

Many of the algorithms and modes disclosed herein can allow seamless integration with mobile handsets, as the handset itself must be unaware that it is transmitting through a directional antenna, since the electronically steerable directional antenna functions autonomously and is able to ensure optimal antenna conditions at all times.

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. What has been described above is merely illustrative of the application of the principles of the invention. Those skilled in the art can implement other arrangements and methods without departing from the spirit and scope of the invention

Claims

WHAT IS CLAIMED IS

1. An electronically steerable directional antenna (ESDA) system comprising a) n antenna elements, wherein n is equal to or greater than 4; b) a phase bank for associating respective phase states with respective signals passing therethrough, the signals with respective phases applied to respective antenna elements to form and steer an antenna beam; c) a 1 : n splitter for splitting a transmit RF signal into n signals;

. d) a n: 1 combiner for combining n signals into a receive RP signal; e) a switching network for electrical coupling between the antenna elements, the phase bank, the splitter and the combiner; and f) an antenna controller for controlling the ESDA system.

2. The system of claim 1, further comprising a monitoring subsystem that includes: g) a detector; h) a filter; and i) a detection switch for routing the receive RF signal through the filter to the detector;

3. The system of claim 1, wherein phase bank is divided into two sections, a transmit phase bank and a receive phase bank, and wherein the switching network is divided into two switching network sections, a transmit switching section coupled to the 1 :n splitter and the transmit phase bank and a receive switching section coupled to the n: 1 combiner and the receive phase bank;

4. The system of claim 1, wherein the phase bank includes at least n delay lines used to produce the phase states.

5. The system of claim 4, wherein at least some of the n delay lines have different lengths.

6. The system of claim 4, wherein only some of the delay lines have equal lengths.

7. The system of claim 1, further including: g) a power amplifier coupled to the 1 :n splitter; and h) a low noise amplifier coupled to the n: 1 combiner.

8. The system of claim 2, wherein a part of the system is implemented in a semiconductor chip.

9. The system of claim 8, wherein the part implemented in a semiconductor chip includes only the l:n splitter, the n:l combiner, the switching network and the antenna controller.

10. The system of claim 9, wherein the part implemented in a semiconductor chip further includes the antenna elements.

11. The system of claim 10, wherein the part implemented in a semiconductor chip further includes the monitoring subsystem.

12. The system of claim 1, wherein the entire ESDA system is implemented in a semiconductor chip.

13. The system of claim 1 , incorporated in a mobile phone.

14. A method for implementing an electronically steerable directional antenna comprising the steps of: a) providing at least four antenna elements; b) applying a signal with a respective phase to each antenna element, each respective phase formed in a phase bank; and c) forming and steering an antenna beam using the signals with respective phases.

15. The method of claim 14, wherein the respective phase of each signal is implemented in the phase bank using delay lines.

16. The method of claim 14, wherein the delay lines have different lengths, thereby providing respective different phases.

17. The method of claim 14, wherein the step of applying a signal includes applying a signal to each antenna element wherein only some of the respective phases are different.

18. A method for implementing an ESDA comprising the steps of: a) providing n antenna elements, wherein n is at least 4; b) in a transmit path, using a phase bank to phase-shift respective phases of at least some of n signals passing therethrough to provide at least some exiting signals having potentially different phases, and applying the exiting signals to respective antenna elements to obtain a directional beam of a transmit signal; and, c) in a receive path, using a phase bank to phase-shift respective phases of each of n signals passing therethrough to provide n exiting signals having identical or similar phases, and combining the identical or similar phase signals into a single receive signal.

19. The method of claim 18, wherein the steps of using a phase bank to phase- shift respective phases includes phase-shifting by using delay lines included in each phase bank.

20. The method of claim 18, wherein in the transmit path, the n signals passing therethrough are obtained by splitting a single signal using a 1 :n splitter and wherein the combining the identical or similar phase signals into a single receive signal includes combining the n signals using a n: 1 combiner.