Abstract: Abstract: A planar antenna assembly (AA) for an RF communication module, comprises i) a conductive plate having a first linear side of a first length and in which is defined a first notch (N1) of a first width and a first electrical length, equal to a quarter of a wavelength corresponding to a chosen frequency of a working frequency band, and comprises a straight part having an open end (OE1) found on the first side, and a shortened end (SE1), and ii) a first feed line (FL1) defined above the conductive plate and across the first notch (N1) and arranged to be coupled to this first notch (N1) to enable wideband operation. The first length of the first side is equal to half this wavelength. Moreover, the first notch open end (OE1) is present approximately in the middle of the first side.

Abstract: A body-worn personal communications apparatus that includes a physically-short electric antenna that is physically smaller in at least one dimension than its electrical length in that same dimension, a transceiver connected to the antenna, a microphone connected to the transceiver, and a casing having a height that is less than its width and its length. The microphone is disposed within the casing, and the antenna is mounted such that the one dimension of the antenna is aligned with the height of the casing.

Abstract: An antenna arrangement for a radio communications apparatus such as a mobile phone, comprises a substantially planar patch conductor having a first feed connection point for connection to radio circuitry and a second feed connection point for connection to a ground plane, a first, differential slot in the patch conductor between the first and second connection points and a second, dual band slot located in the patch conductor outside the area between the first and second connection points. The length of the first slot is greater than a quarter wavelength, and provides a third resonant frequency increasing the bandwidth of the antenna. The width of the patch conductor between the first and the second slots is selected to obtain a low impedance transformation and thereby a low antenna resistance causing detuning the antenna. A user holding the phone increases the antenna resistance thereby tuning the antenna.

Abstract: A wireless terminal for use in the transmitting and receiving frequency bands of a frequency duplex system comprises transmitting and receiving stages (Tx, Rx) and signal propagating means (22, 24, 26) coupled to the transmitting and receiving stages. The signal propagating means comprises a narrow band antenna structure (24), such as a Planar Inverted-F Antenna (PIFA), having sufficient bandwidth to cover the larger one of the transmitting and receiving frequency bands and a BAW receiving filter (26) and a BAW transmitting filter (22) coupled by respective feeds to the antenna structure (24). The filters (22, 26) enable the antenna structure to have a small volume and be reusable at different FDD frequencies.

Abstract: In a body-worn personal communications apparatus, for example a wrist-carried wireless telephone, an antenna (102) is a helical or other physically-shortened electric antenna that makes use of the enhanced normal component of electric field close to the body. A microphone (114) can act as a top load to the antenna, thereby enabling the use of a shorter antenna. The antenna (102) may be formed from coaxial cable, enabling it to provide electrical connections between the microphone (114) and transceiver circuitry in the body of the apparatus. By arranging for the microphone (114) to have low impedance at radio frequencies, the coaxial cable acts as an inductive stub and enables the antenna (102) to be further shortened.

Abstract: A communications apparatus, such as a portable radiotelephone, comprises a housing (40) containing a printed circuit board (PCB) (12) having a ground plane (16) and electronic components in rf shields (18) thereon. A planar antenna (10), for example a planar inverted-L antenna (PILA), is mounted spaced from the ground plane and a dielectric (14), for example, air, is present in a space between the PCB and the planar antenna. A feed (36) couples the planar antenna (10) to the rf components. The feed comprises parallel L-C resonator circuit components (42), a transmission line, or any other predominantly reactive network for reactively tuning the antenna. In the case of a dual band antenna the components are selected so that a lower frequency is tuned inductively and a higher frequency is tuned capacitively. The components, which may be discrete or distributed, are mounted on the PCB or a part of the planar antenna structure which is not subject to detuning by the user in normal operation of the apparatus.

Abstract: An antenna arrangement comprises a patch conductor (102) supported substantially parallel to a ground plane (104). The patch conductor includes first (106) and second (108) connection points, and further incorporates a slot (202) between the first and second points. The antenna can be operated in a first mode when the second connection point is connected to ground and in a second mode when the second connection point is open circuit. By connection of a variable impedance (514), for example a variable inductor, between the second connection point and the ground plane, operation of the arrangement at frequencies between the operating frequencies of the first and second modes is enabled.

Abstract: An antenna arrangement includes aground conductor (302) incorporating two slots (304a,304b) having an electrically small separation and connections (308a,308b) for coupling a transceiver to each slot to enable the ground conductor to function as two substantially independent antennas. Such a device enables efficient diversity performance to be obtained from small volume. The ground conductor, slots and transceiver are integrated in a module (206) adapted for connection to a further ground conductor which provides the majority of the antenna area. The further conductor would typically be a printed circuit board ground plane or mobile phone handset. Matching and broadbanding circuitry may conveniently be incorporated in the module. By varying the area of the connections between the module and the further ground conductor, the resonant frequencies of the slots can be modified.

Abstract: An antenna diversity arrangement is applicable to frequency hopping receiver (34) for receiving data packets transmitted on frequency channels lying within an overall frequency bandwidth, divided into a plurality of sub-bands. In each sub-band the frequency characteristics of the channel will be substantially the same. The choice of antenna (10, 12) for a particular sub-band is done by carrying-out frequency diversity measurements and the selection is treated as being valid for a period of time which may be preset or determined dynamically. In operation the hopping sequence is known to the receiver so that it can determine in advance the frequency of the next data packet to be received and can select the particular antenna without the necessity of carrying out diversity measurements. At the end of the time period the suitability of the selected antenna is checked and if necessary the selection is updated in the receiver.

Abstract: A wireless terminal having a dual band antenna arrangement which comprises a planar inverted-F antenna (10) having a first (12) for signals in a first, lower frequency band, for example the GSM band, a second feed (14) for signals in a second, higher frequency band, for example the DCS band, and a ground pin (16). A first coupling stage (26A) couples the transmit and receive paths of a first transceiver (GSM) to the first feed and a second coupling stage (26B) couples the transmit and receive paths of a second transceiver (DCS) to the second feed. Each of the first and second coupling stages comprise a quarter wavelength transmission line (50A, 50B) having a first end coupled to the respective transmit signal path and a second end coupled by band pass filter (52A, 52B) to the respective receive signal path.

Abstract: In an ad-hoc radio communication system comprising a plurality of stations (100) formed into at least one network (102a,102b), each station (100) is assigned a rank representative of its suitability for performing the role of master station in a network (102a). The rank may for example be assessed depending on the performance of the station's antenna (204) or its access to mains power. It is arranged that the station (100) having the highest rank in a network (102a,102b) performs the role of master for that network, thereby improving the efficiency of communication in the network.

Abstract: A capacitively back-coupled wireless terminal (10) comprises a PCB (22) having a ground conductor (24) on one surface. A back coupling capacitor (C) is carried by the ground conductor. An elongate slot (30) is provided in the ground conductor to widen the bandwidth. An electromagnetic shield (32) is provided on the side of the PCB (22) which in use is facing a lossy dielectric in order to reduce the SAR. The shield is disposed adjacent to, but spaced from, the slot (30) in the ground conductor and the back coupling capacitor. For narrowband operation the slot may be omitted and/or the spacing between the PCB (22) and the shield (32) may be reduced.

Abstract: A personal communications apparatus comprises an elongate body 202 incorporating an antenna diversity arrangement in which first and second antennas (102A, 102B) are located at opposite ends of the body. In one embodiment a microphone (114) is located at the tip of one antenna (102A) and a loudspeaker (116) at the tip of the other antenna (102B). The microphone (114) and loudspeaker (116) act as top loads to their respective antennas, thereby enabling the use of shorter antennas. The antennas (102A, 102B) may be formed from coaxial cable, enabling them to provide electrical connections between the microphone (114) or loudspeaker (116) and transceiver circuitry in the body of the apparatus. By arranging for the microphone (114) and loudspeaker (116) to have low impedances at radio frequencies, the coaxial cable acts as an inductive stub and enables the antennas (102A, 102B) to be further shortened.

Abstract: An antenna diversity arrangement (200) comprises a plurality of antennas (204a, 204b) capable of forming a plurality of antenna beams. The amplitude and phase relationships between the signals driving each of the antennas (204a, 204b) are first determined for an arrangement where each antenna is replaced by a point source. The results of this analysis are then transformed by reference to the characteristics of the real antenna arrangement (200) to determine appropriate driving signals. The resultant antenna diversity arrangements (200) can have antennas (204a, 204b) located arbitrarily close to one another with near-zero correlation between any pair of the antenna beams, thereby providing a compact and effective arrangement.

Abstract: An antenna arrangement (300) comprises a ground conductor (102) on which is mounted an antenna (304). The antenna is small relative to a wavelength at operational frequencies of the antenna arrangement (300) and the dimensions of the antenna (304) are selected so that the combined impedance of the antenna (304) and ground conductor (102) is suitable for driving via a conventional matching circuit. This condition is met when the bandwidth of the arrangement is dominated by that of the antenna and ground conductor, rather than that of the matching circuit. In one embodiment the antenna is a triangular conducting element which is considerably wider than its height, the length being sufficient to to give a reasonable resistance and the width being sufficient to reduce the reactance to a level that can reasonably be matched.

Abstract: A wireless terminal having antenna diversity comprises a transceiver coupled to a plurality of antenna feeds and a ground conductor (902), the antenna feeds being coupled directly to the ground conductor (902). In one embodiment the ground conductor is a conducting case (902). The coupling may be via parallel plate capacitors (504) formed by a respective plate (506) and a surface (908) of the case (902). The case (902) acts as an efficient, wideband radiator, eliminating the need for separate antennas. Slots (912) may be provided to increase the radiating bandwidth of the terminal and improve its diversity performance. Good diversity performance is obtained in a range of environments, whether the terminal is hand-held or free-standing.

Abstract: An antenna arrangement comprises a patch conductor (102) supported substantially parallel to a ground plane (104). The patch conductor includes first (106) and second (108) connection points, for connection to radio circuitry, and further incorporates a slot (202) between the first and second points. The antenna can be operated in a plurality of modes by variations in the impedances connected to the first and second points. For example, if signals are fed to the first point (106) then a high frequency antenna is obtained by connecting the second point (108) to ground and a low frequency antenna by leaving the second point (108) open circuit. A wide range of embodiments having alternative connection arrangements are possible.

Abstract: An antenna diversity system includes at least two antennas. Each antenna may be connected via a common connection point to a receiver by a respective switch which presents a low impedance connection between the antenna and receiver in the on state and a substantially reactive load to the antenna in the off state. Selection of appropriate impedances for the off state load enables the antennas to function as an array with a variety of beam patterns depending on the state of the switches. Cycling through a sequence of switch states steers the antenna beam providing improved resistance to fading and multipath effects. Alternatively, the antennas may be connected to a hybrid coupler, which enables two beam patterns to be available simultaneously for signal quality measurement and comparison.

Abstract: An antenna arrangement comprises a patch conductor (102) supported substantially parallel to a ground plane (104), a feed pin (106) connected to the patch conductor at a first point and a ground pin (108) connected between a second point on the patch conductor and the ground plane. The feed and ground pins are connected by a linking conductor (510) and have shunt capacitance means coupled across them. Suitable values of the capacitance means and the location and dimensions of the linking conductor enable a good match to the antenna to be achieved. The linking conductor may be directly connected to the patch conductor or there may be gaps between the feed and ground pins both above and is below the linking conductor. An impedance transformation may be provided by the feed and ground pins having different cross-sectional areas and/or by the provision of a slot in the patch conductor.

Abstract: A personal communications apparatus, for example a cellular telephone handset, has an antenna diversity arrangement comprising first and second antennas (102A, 102B) arranged with their polarisation axes slanted with respect to the median plane of the handset body (218). By a suitable choice of inclination angles one of the antennas can be arranged to be substantially vertical in use, whether by right or left handed users, thereby improving received signal strength from a vertically polarised base station. The arrangement also enhances diversity operation, since the correlation between the field strengths received by the antennas is reduced by their relative orientation. When the apparatus is used in a system employing a Code Division Multiple Access (CDMA) techniques, the apparatus preferably includes a 2D Rake receiver for mitigating the effects of multipath fading and interference.