Abstract: An adjustable matching network is provided for a wireless communications device transmitting and receiving signals in multiple frequency bands via an antenna. The adjustable matching network selectively connecting the antenna to a select power amplifier corresponding to a selected transmit frequency band and automatically matching the impedance of the antenna to the select power amplifier. The adjustable matching network also selectively connecting the antenna to a select bandpass filter corresponding to a selected receive frequency band and automatically matching the impedance of the antenna to the select bandpass filter.

Abstract: An adjustable matching network is provided for a wireless communications device transmitting and receiving signals in multiple frequency bands via an antenna. The adjustable matching network selectively connecting the antenna to a select power amplifier corresponding to a selected transmit frequency band and automatically matching the impedance of the antenna to the select power amplifier. The adjustable matching network also selectively connecting the antenna to a select bandpass filter corresponding to a selected receive frequency band and automatically matching the impedance of the antenna to the select bandpass filter.

Abstract: Dual-band retractable radiotelephone antennas have an elongated antenna element, a top load element, and a trap positioned between and electrically connected to the elongated antenna element and the top load element. The trap facilitates obtaining half-wave monopole performance at a first frequency band and half-wave monopole performance at a second higher frequency band.

Abstract: An electronic device, such as a radiotelephone, has a magnetic latch that maintains a flip cover in a closed position and an electromagnetic release conveniently positioned for one-handed operation by a user. A first magnetic object is disposed within the housing and a second magnetic object is disposed within the flip cover so as to be magnetically attracted to the first magnetic object when the flip cover is in the closed position. The first and second magnetic objects are configured such that the magnetic attraction force therebetween is greater than the biasing force of the spring member to maintain the flip cover in the closed position. A user-activated magnetic field generator is disposed adjacent to at least one of the first and second magnetic objects and reduces the magnetic attraction force between the first and second magnetic objects relative to the biasing force of the spring member such that the flip cover is urged to the open position.

Abstract: Radiotelephones configured with integrated matching circuit components in the housing and antenna are disclosed. The present invention configures the antenna and the associated housing receiving passage to define a capacitor and inductor to match the differing impedances generated by retractable top load antennas (retracted and extended impedances) without requiring a separate switching circuit and wiping contacts.

Abstract: A novel method and apparatus are described for reducing the effect that magnetic field emissions from a radio telephone may have on devices sensitive to time-varying magnetic fields. The variance of the magnetic field is smoothed by the addition of a smoothing capacitor having a time constant significantly longer than the TDMA time frame which is connected in parallel with the transmitter. In addition, a counter-balancing magnetic field is generated by a field canceling loop connected in series with the transmitter which causes current to flow in a path approximately opposite from the path the current flows through the battery, in roughly parallel plane. The current flowing through the field canceling loop generates a magnetic field approximately coaxial with, and opposite in polarity from, the magnetic field generated by current flowing through the battery, partially negating the latter.