Abstract: A diversity reception apparatus having a simple configuration which includes only one AD conversion unit and receives analog modulated signals is provided. The diversity reception apparatus includes a switching unit that analog-multiplexes signals received by two antennas using time-division method and is placed in front of an AD conversion unit. The apparatus also includes a time-division separation unit that (i) obtains time-division multiplexed signals digitized by driving at the same frequency as driving frequency of the AD conversion unit and (ii) separates the time-divided signals into a signal per antenna. Moreover, the apparatus includes signal quality judgment units that judge each signal quality of the time-divided signals and a composition unit that executes composition processing based on the signal quality.

Abstract: A relaying device for providing optimum communication between a non-contact information medium and an information read/write device, and a communication system employing the relaying device, in which the adverse effect on communication, brought about by limitations on the mounting site of the information read/write device may be eliminated. The relaying device is formed by a resonance circuit 34 including a first antenna coil 31, electro-magnetically coupled to an antenna coil 11 of the information read/write device 10, a second antenna coil 32, connected in series with the first antenna coil 31 and electro-magnetically coupled to an antenna coil 21 of the non-contact information medium 20, and a tuning capacitor 33 connected in series with the first antenna coil 31 and the second antenna coil 32.

Abstract: A multiple band antenna has an RF coupling structure (110) and a resonant RF structure (102). The RF coupling structure (110) has an RF connection (116, 118) and an RF coupling end (112, 114). The resonant RF structure (102) is reactively coupled to the RF coupling end (112, 114). The resonant RF structure (102) has a first end (106) and a second end (108) and has a conductive perimeter (102) enclosing at least one slot area (104) configured to induce an additional resonant RF band for the resonant RF structure (102). The first end (106) and the second end (108) are reactively coupled to a ground plane (124, 120) to facilitate longer wavelength operation. Cellular phones (800) and wireless communications sections incorporating such antennas are also provided.

Abstract: A technique for steering a directional antenna such as may be used with User Equipment (UE) in a wireless communication system. Optimum angle settings for the directional antenna are determined as different values for an uplink and downlink; that is for simple reception and simple transmission. Thus, rather than determine compromised directions that are picked in an attempt to optimize transmission and reception with the same directional setting, directional settings may be optimized independently. The invention is of particular use in a Time Division Duplex (TDD) system where transmit and receive functions can be operating independently at different times. In further aspects, an optimum direction is determined by estimating an interference signal power which is detected from signals emanating from adjacent base stations (access points) and determining a directional setting that minimizes interference to adjacent cells based upon such measurements.

Abstract: A system and method for providing dynamic allocation of MIMO communication resources during a single communication. Various aspects of the present invention may comprise determining a first set of MIMO communication resources to utilize for communicating a first portion of a unit of information. The first set of MIMO communication resources may be allocated for communicating the first portion of the unit of information. A second set of MIMO communication resources may be determined to utilize for communicating a second portion of the unit of information, where the second set of MIMO communication resources is different from the first set of MIMO communication resources. The second set of MIMO communication resources may be allocated for communicating the second portion of the unit of information. The first and second portions of the unit of information may, for example, be communicated consecutively or concurrently.

Abstract: A diversity antenna arrangement to reduce cost and the number of switching operations between different antennas includes an antenna changeover switch for switching between antennas, and an evaluation circuit for evaluating reception quality of a signal derived from a signal received from at least one of the antennas and conveyed to a receiving device via the antenna changeover switch. The evaluation circuit emits an evaluation signal based on the determined reception quality. A control device drives the antenna changeover switch based on the evaluation signal. A weighting device, using a first coefficient, weights the signal conveyed to the receiving device via the antenna changeover switch, and using a second coefficient, weights a signal received from at least one further antenna. A summing circuit adds the weighted signals. A regulating circuit generates the coefficients to minimize the temporal amplitude fluctuations of the composite signal, which is evaluated by the evaluation circuit.

Abstract: In a first embodiment, the invention relates to an arrangement for operating a plurality of terminal devices (6) on a common antenna (4) with a coupling network (2) comprising a first separator (8) associated with the antenna (4) and a second separator (10) associated with the respective terminal (6). In a second embodiment, the invention relates to an arrangement for operating a plurality of terminal devices (6) on a common transmitting antenna (4?) and on a common receiving antenna (4) which is separate from the common transmitting antenna (4?) with a coupling network (2) comprising a separator (10) which is associated with the respective terminal.

Abstract: A receiving apparatus which appropriately selects one out of a plurality of antennae for reception. The receiving apparatus is provided with a reception means for receiving a radio wave via an antenna selected out of the plurality of antennae by a selection means, a reception level signal creation means for creating a reception level signal indicative of reception electric field strength for the received radio wave, an extraction means for eliminating the basic wave components of the radio wave from the reception level signal to create the multiple propagating components of the radio wave in the reception level signal as a multiple propagating wave strength signal, and a reception level signal correction means for correcting the reception level signal by using the multiple propagating wave strength signal to create a corrected reception level signal without the multiple propagating wave components.

Abstract: A telecommunication system uses a satellite antenna showing on the horizontal plane, a sufficiently narrow radiation lobe to discriminate two adjacent satellites and showing on the vertical plane, a sufficiently narrow vertical lobe to ensure an adequate gain, but sufficiently ample to enable the reception of a certain number of satellites in adjacent orbital positions, by land stations distributed over a certain meridian arc without the necessity for antenna elevation angle variations.

Abstract: A method and apparatus are provided that allows beamforming to be used on a user-specific signal together with a sector-wide pilot signal in a communication system, such as a CDMA system. In one embodiment, the invention includes transmitting a pilot signal with a wide beamwidth to a remote terminal from a first array, transmitting a first traffic signal with a narrow beamwidth directed to the remote terminal from the first array, and transmitting a second diversity traffic signal with a second narrow beamwidth directed to the remote terminal from a second array. In some examples, the invention may also include transmitting a second pilot signal from the second antenna array.

Abstract: An antenna detection and diagnostic system and associated method, including current and voltage detection circuits, are disclosed for detecting antenna failure mechanisms for integrated radio receivers. Integrated current limit detection circuitry is disclosed that determines current levels drawn by a remotely mounted antenna and generates a drive signal that controls a current limiting pass transistor such that current flow through the transistor is reduced when the detected current level drawn antenna rises above a current limit level. Integrated current and voltage detection circuitry is disclosed that detects current and voltage levels drawn by a remotely mounted antenna and determines under-current, over-current, and over-voltage antenna error conditions. At least one antenna error output pin for the integrated radio receiver is then used provide an output signal indicative of antenna error conditions.

Abstract: A radio-communication terminal device having an antenna unit incorporating an antenna element and an authenticator for authenticating the connected antenna element, and a transceiver unit that includes a transmission circuit, a reception circuit, an authentication detector and a communication controller. The antenna unit further includes a first antenna connector and a first connector. The transceiver unit includes a second connector that connects to the first connector when the first antenna connector connects to the second antenna connector. The authentication detector detects the authentication of the authenticator when the first connector is connected to the second connector. The communication controller prevents the transmission circuit from transmitting signals when the authenticator cannot authenticate the connection to the antenna unit.

Abstract: A radio communication apparatus using an array antenna has a plurality of reception branches for conveying reception signals received at the antenna element of the array antenna, and a calibration branch for selecting one of the plurality of reception branches and conveying the reception signal. Channel estimations are made respectively on the reception-branch signals and a calibration-branch signal. RAKE composition is made on the channel estimation values, a result of which is used to detect amplitude and phase deviations on the reception branch thereby carrying out a correction.

Abstract: A system and method is provided for full-duplex antenna impedance matching. The method comprises: effectively resonating a first antenna at a frequency selectable first channel in a first frequency band; generating a first antenna impedance at the first channel frequency; effectively resonating a second antenna at a frequency selectable second channel in the first frequency band; generating a second antenna impedance at the second channel frequency; supplying a first conjugate impedance match at the first channel frequency; and, supplying a second conjugate impedance match at the second channel frequency. For example, the first antenna may be used for transmission, while the second antenna is used for received communications. The antennas effectively resonant in response to: supplying frequency selectable conjugate impedance matches to the antennas; generating frequency selectable antenna impedances; and/or selecting the frequency of antenna resonance.

Abstract: The invention relates to a wireless instrument (1) includes a wristband (2) having a first (2a) and a second (2b) band portions connected to opposite edges of a casing (3), each of the first and second band portions having upper and lower surfaces. A first (4a) and a second (4b) loop antennas are embedded respectively in the first and second band portions and extend between the corresponding upper and lower surfaces, both loop antennas being connected through the opposite edges of the casing to a first (5a) and a second (5b) tuning circuits. the first and second tuning circuits are connected to an antenna receiver (6) arranged in said casing and together in a hybrid manner via an interconnection circuit (7), both tuning circuits being connected partially in parallel and partially in series.

Abstract: A communications network, in particular for telephony, comprises at least one operator a plurality of remote units for exchanging signals with mobile terminals and an interface unit for controlling the data traffic between the operator and the remote units. The interface unit is connected to the remote units by a first transmission support in which the main signal propagates. The main signal is divided into a plurality of secondary signals, each identified by a preset parameter value. Each remote unit is designed to process at least one secondary signal selected from amongst the secondary signals into which the main signal is divided. The secondary signal is identified by the remote unit according to the above-mentioned present parameter value.

Abstract: A diversity apparatus for a mobile communication terminal with a GPS function. The diversity apparatus comprises: a first multiband antenna with a first reception polarization characteristic, for receiving a combined RF signal of a GPS signal and a mobile communication signal; a second multiband antenna with a second reception polarization characteristic distinguished from the first reception polarization characteristic, for receiving a combined RF signal of a GPS signal and a mobile communication signal; and a switching diversity unit for selecting one of the RF signals received by the first and second multiband antennas.

Abstract: A system and method for determining an optimal antenna position of a directional antenna in a wireless communication system are described. The optimal antenna position is determined by calculating a steering metric value for possible antenna positions and the antenna position with the highest steering metric value is selected as the optimal antenna position.

Abstract: It is an object of the present invention to provide an indoor mobile communication device having a simple structure, providing a sufficient communication range, and also providing for stable communication with a small fading effect.

Abstract: A microstrip patch antenna having high gain and wide band is disclosed. The microstrip patch antenna includes: a first patch antenna layer for radiating a energy supplied from transmitting/receiving feeding circuit and a first radiation patch electrically coupled to the first dielectric layer and supplying the energy to a receiving feeding circuit electrically coupled with the first radiation patch, wherein the energy is supplied by electromagnetic coupling of a first parasitic patch and second parasitic patch; a second patch antenna layer for improving impedance bandwidth of energy received through the first parasitic patch arranged in between the second dielectric layer and the third dielectric layer and radiating the improved impedance bandwidth; and a third patch antenna layer for improving a gain of the energy received through the second parasitic patch arraigned in between the fourth dielectric layer and the fifth dielectric layer.

Abstract: A mobile unit 40 which is in a soft handoff condition 50 with a base station (32) has the power transmitted by the base station (32) on the mobile link (52) controlled. The base station (32) determines (70) when a frame erasure count reaches a particular level N. The base station then places this link in a clamped state (72) at minimum power. When the base station determines that M consecutive good frames have been received (92), the base station restores the link (52) to a normal state (94). A recovery arrangement (100, 110 and 120) prevents clamping by all base stations (32–34) and loss of the link.

Abstract: A radio-frequency (RF) apparatus includes front-end circuitry. The front-end circuitry includes a filter circuitry and an impedance matching circuitry. The filter circuitry has a differential output that has an output impedance. The filter circuitry filters signals outside a signal band of interest. The impedance matching network has a differential input coupled to the output of the filter circuitry. The impedance matching network also has a differential output coupled to a signal processing circuitry. The signal processing circuitry has an input impedance. The impedance matching network matches the input impedance of the signal processing circuitry to the output impedance of the filter circuitry.

Abstract: A system and method for confirming that two antennae are connected to a radio receiver. There is provided a radio receiver including a signal generating source, a first antenna feed connection port, a second antenna feed connection port, and a signal detection circuit. Also provided is a low noise amplifier (LNA) module having a first LNA and a second LNA, wherein the first LNA is in communication with a first antenna and the second LNA is in communication with a second antenna, and wherein outputs of the first and second LNAs are in communication, respectively, with the first antenna feed connection port and the second antenna feed connection port. A DC signal pathway is established, at least in part, through the LNA module and electrically connects the signal generating source and the signal detection circuit to each other, whereby when the signal is detected it can be confirmed that both antennae are connected to the radio receiver.

Abstract: The present invention provides a wireless device including: at least an antenna; and at least a conductive ground serving as a ground, through which a high frequency current flows, and the conductive ground having at least a side which is approximately one quarter wavelength of a radio wave transmitted from the antenna, the at least side of the conductive ground having a feeding point, at which the antenna is electrically connected to the conductive ground, wherein the feeding point on the side is positioned closer to one end of the side than a center position, so that the feeding point is positioned asymmetrical to the conductive ground in any directions included in a plane parallel to the conductive ground, whereby the high frequency current flowing, through the conductive ground has an asymmetrical distribution of current over the conductive ground.

Abstract: A method provides a technique for optimally combining communication beams. The method forms a plurality of beams from captured signals. One beam is selected as the primary beam while a subset of the others are applied to auxiliary receivers. A digital signal processor weights and combines these primary and secondary beams.

Abstract: A portable computer having a main board; an antenna receiving and transmitting an RF signal; a PCI slot part provided in the main board and receiving the RF signal received and transmitted through the antenna; a wireless LAN card including a main card removably inserted into the PCI slot part, and an RF connector provided at a side of the main card and through which the RF signal is inputted/outputted between the antenna and the PCI slot part; and an antenna connecting part connected to the RF connector and allowing the RF signal to be inputted/outputted through the RF connector between the antenna and the PCI slot part when the wireless LAN card is inserted into the PCI slot part. With this configuration, the present invention provides a portable computer improved in a mounting structure of a wireless LAN card doing not have an antenna.

Abstract: A distributed antenna system comprising a plurality of antenna elements, duplexers and amplifiers, each amplifier and duplexer operatively coupled with one of said antenna elements and mounted closely adjacent to the associated antenna element in such a manner as incidences of insertion loss, noise and system failure are reduced.

Abstract: The present invention relates to low-cost improvement of performance of multiple radio wireless access points. It relates to combinations of an antenna and one or more of a filter or an active components such as a power amplifier, low noise amplifier, switching diode or RF phase shifter (with a plurality of antennas), connected to the antenna connector of a radio component. Particular aspects of the present invention are described in the claims, specification and drawings.

Abstract: In a GPS receiver system having a navigation GPS receiver unit and an assisted GPS receiver unit, a coupler is connected between a navigation GPS receiver and an assisted GPS receiver. A navigation GPS antenna is shared between the navigation GPS receiver and the assisted GPS receiver. With this configuration, an additional antenna for the assisted GPS receiver is not required. Therefore, the total number of parts included in the system is not increased.

Abstract: According to some aspects of this invention, a compact, broadband active receiving antenna uses one or more high transconductance transistors such as Field Effect Transistor(s) paired with another Transistor and arranged in a Cascode amplifier configuration. Some embodiments involve a single high transconductance transistor arranged with a high efficiency transformer in a nondissipative feedback loop to improve linearity and dynamic range. The devices have a high input resistance, low input capacitance, low noise and a very high second and third order Intercept Point. Since the gain is primarily a function of the amplifying electronics, it is not necessary to increase the directivity of the antenna to achieve higher gain.

Abstract: A multi-carrier receiver selects antennas (A31, A32), i.e. carriers whereto a small amount of power and data is allocated, for estimation of characteristics of a narrowband disturber (RFI-Signal-3) in the Radio Frequency Interference band (RFI-Band), a predetermined band for e.g. radio amateur transmission. These antennas (A31, A32) can be selected amongst all carriers located inside the Radio Frequency Interference band (RFI-Band) and at least two carriers (C1, C2) located outside the Radio Frequency Interference band (RFI-Band).

Abstract: An antenna assembly has an antenna set, a rotation assembly and a control circuit for driving the rotation assembly to rotate to adjust receiving angel of the antenna set. The control circuit can learn to adjust remote signals represented different channel number on a remote control to automatically control the receiving angle and direction of an antenna set. Thus, the antenna assembly can be suitable to general remote control to automatically adjust the antenna set to search the wireless bands. Besides, the control circuit further stores data related to the wireless bands with the corresponding channel number to be easy for user turn to specific wireless band without searching step.

Abstract: For one embodiment, a short-range, wireless communication link, such as a Bluetooth link, is established between a mobile phone and a computer system. The mobile phone transmits an access code via the link to the computer system. The access code is generated using data stored in the subscriber identity module (SIM) in the mobile phone. Access to the computer system is granted in response to receiving the access code. In this manner, the SIM is used not only to identify the user during cellular phone calls (or other long-range, wireless communication) but also to authenticate the user and to gain access to a computer system.

Abstract: A low-cost diversity antenna switching system and method is realized by controlling bias voltages on PIN diodes. By increasing the reverse bias voltage impressed upon a PIN diode, an RF signal impressed upon the diode is increasingly attenuated. As the PIN diode is forward biased to conduct in the forward direction, RF attenuation decreases. Two or more PIN diodes are used to increasingly attenuate signals from one antenna as attenuation of signals from another antenna is gradually decreased. The progression of the bias voltages is accomplished using a microprocessor that monitors a received signal strength indicator (RSSI) signal from a radio receiver. The RSSI is used to control which of two antennas are coupled into the receiver by predicting a signal fade.

Abstract: It is an object of the invention to provide a connection structure for connecting the dielectric strip of an NRD guide with a metal waveguide, in which the conversion loss (connection loss) for high-frequency signals is reduced, and in which the NRD guide as well as the millimeter wave integrated circuit in which the NRD guide is incorporated can be made smaller. A non-radiative dielectric waveguide is made by arranging a dielectric strip for propagating high-frequency signals between parallel planar conductors arranged at a spacing of not more than half the wavelength of a high-frequency signal, a conductive member being arranged at an end face of a terminal end of the dielectric strip. An aperture is formed in at least one of the parallel planar conductors at a location where the electrical field of an LSM mode stationary wave propagating along the dielectric strip becomes largest. An open terminal end of a metal waveguide is connected to this aperture.

Abstract: A radio frequency connector that protrudes through a printed circuit board is comprised of threaded leads. A center conductor is shielded when a shielding connector cap, having a threaded inner portion, screws onto the threaded leads.

Abstract: An apparatus for transferring electromagnetic energy intermediate a host device and a medium or free space adjacent to the apparatus in an impulse radio system includes: (a) an energy guiding means for guiding the electromagnetic energy; the energy guiding means is connected with the host device; (b) an electromagnetic energy channeling structure effecting the transferring and including a plurality of gap interfaces; and (c) a transition means for coupling the energy guiding means with at least one gap interface of the plurality of gap interfaces. The transition means conveys the electromagnetic energy intermediate the energy guiding means and the at least one gap interface. The at least one gap interface intersects the transition means in a substantially continuous curve in selected planes intersecting the gap interface and the transition means.

Abstract: A method and device are provided for determining distributed signal sources of a base station that includes a pair of circular array antennas that maintain a predetermined distance from each other. The method and device may estimate primary central vertical angles of the distributed signal sources received by each sensor according to TLS-ESPRIT, for example. The method and device may further convert a 2-dimensional cost function into a first 1-dimensional cost function by using the estimated primary central vertical angles of the distributed signal sources. Central horizontal angles may be estimated by making the first 1-dimensional cost function have a maximum. The 2-dimensional cost function may be converted into a second 1-dimensional cost function by using the estimated central horizontal angles of the distributed signal sources. The central vertical angles may be estimated by making the second 1-dimensional function have a maximum.

Abstract: A radio receiver system having a plurality of receiving antennas and a plurality of receivers is described in which antenna signals of a multiplicity of the plurality of receiving antennas are fed to each of the plurality of receivers. The plurality of receiving antennas may be interconnected to the plurality of receivers more flexibly as a function of the desired reception strategy. In addition, the functionality of the entire system may also be maintained in the event of a defect or failure of one or more receiving antennas.

Abstract: A method for selecting an antenna direction setting for optimum signal reception prior to channel equalization provides a set of metrics, referred to as channel quality metrics (CQM), that characterize the quality of the received signal for a given antenna setting and a generic algorithm that uses these metrics to select the antenna setting for an optimum reception. This invention utilizes five main CQMs: a Signal Strength Metric (SSM), a minimum mean squared error of a decision feedback equalizer (MMSE (DFE)) channel quality metric, a MMSE for a linear equalizer (MMSE(LE)) channel quality metric, a Spectral Flatness Metric (SFM) and an interference degradation metric (IDM).

Abstract: A radio station including two antennas combined with respective first and second hybrid transmission polarization couplers is disclosed. Each antenna is arranged to generate two orthogonal electric field components in response to two respective quadrature radio signals from the corresponding polarization coupler. The station further includes at least one hybrid distribution coupler with a first output connected to a first input of the first polarization coupler and a second output connected to a first input of the second polarization coupler and at least one radio signal source delivering a radio signal to a first input of the distribution coupler.

Abstract: A radio system having a hub transceiver and a plurality of customer premise transceivers at different distances from the hub transceiver. Each of the customer premise transceivers includes an antenna for transmitting an upstream radio signal to the hub transceiver and receiving a downstream radio signal from the hub transceiver. A selected exchangeable attenuator pad is mounted on the customer premise antenna in the path of the radiated signals for attenuating the upstream and downstream radio signals. The attenuator pad is selected in order to compensate for the different transmission path losses in order to provide a fixed predetermined signal strength in the downstream radio signals to each of the customer premise transceivers and a fixed predetermined signal strength to the hub transceiver from each of the customer premise transceivers.

Abstract: An antenna calibration system consists mainly of a signal source, an antenna, a first radio frequency mixer, a first local oscillator, an power detecting device, a personal computer, and a servo amplifier. The signal source emits a signal, and the antenna receives the signal. The signal and the first local oscillator, which emits a signal, are emitted into the first radio frequency mixer. Then the first radio frequency mixer emits a signal into the energy detecting device which calculates the signal power, and transmits the power into the personal computer. The personal computer calculates the powers, and then transmits an angle control signal into the servo amplifier. The servo amplifier amplifies the signal, and then drives the antenna pedestal to turn until the antenna is aimed at the signal source. This can calibrate exactly the antenna's azimuth and elevation offset angle.

Abstract: A system and method for suppressing spurious signal leakage in a mobile terminal antenna interface without degrading switch linearity or system insertion loss is disclosed. The antenna interface includes an antenna port, a receive port, a transmit port, and a plurality of switch modes, that may include a receive mode, a transmit mode, and a special isolation mode. To suppress spurious signal leakage from high band transmit and receive ports, a switching mechanism is employed to isolate the receive port from the antenna port in high band transmit mode, and to isolate the transmit port from the antenna port in high band receive mode. A special isolation mode allows simultaneous isolation of the high band transmit and receive ports from the antenna port in low band transmit and receive modes. DC current control circuitry is optionally employed to reduce current drain in transmit and special isolation modes, extending battery life.

Abstract: A high-frequency module constituted by an integral laminate for handling a plurality of transmitting/receiving systems having different passbands comprises (a) a switch module part for branching higher-frequency signals and lower-frequency signals and switching connection to the transmitting systems and the receiving systems, (b) a high-frequency amplifying circuit module part, and (c) a phase-adjusting circuit disposed between the switch module part and the high-frequency amplifying circuit module part, wherein the phase matching between the switch module part and the high-frequency amplifying circuit module part via the phase-adjusting circuit is adjusted to conjugate matching in a fundamental frequency band, while it is adjusted in a nonconjugate matching range in n-th frequency bands, wherein n is an integer of 2 or more.

Abstract: An antenna that includes a radiating element and a feed capacitor element is disclosed. The radiating element is at least substantially balanced and the feed capacitor element is capacitively coupled to the radiating element. Also disclosed is a wireless device that utilizes an inverted C-type antenna.

Abstract: An antenna structure which has a platform defining at least six sectors having a vertex contained substantially within the platform. At least six dual polarized antennas are positioned on the platform for transmitting and receiving signals substantially in each of the at least six sectors, respectively.

Abstract: It is an object of the present invention to provide an indoor mobile communication device having a simple structure, providing a sufficient communication range, and also providing for stable communication with a small fading effect.

Abstract: A transmitter of a base station includes a data serial-to-parallel converter, M modulators, M beam formers, and transmission antennas. The data serial-to-parallel converter converts transmission data into M sequences. Each modulator modulates the transmission data. Each beam former weights the modulation signal to form directional beams. The transmission antennas narrow the beams and transmit the modulation signals in parallel (MIMO transmission). In a mobile station, a receiver has reception antennas for receiving data transmitted in parallel and an MIMO demodulator for demodulating the data.

Abstract: According to some embodiments of the present invention, an impedance transformation circuit is provided for use with a transmitter, a receiver, and an antenna. The transmitter may provide transmission signals for transmission by the antenna. The antenna may provide received signals having an associated signal parameter to the receiver. The impedance transformation circuit includes an impedance adjusting circuit and a controller. The impedance adjusting circuit is connected between the antenna, the receiver, and the transmitter. The impedance adjusting circuit is configured to change an impedance difference presented between at least one of: 1) the transmitter and the antenna, and 2) the antenna and the receiver, in response to a control signal. The controller generates the control signal to change the presented impedance difference in response to a signal parameter.