A method is provided for operating a duplexer including a first tunable bandpass filter, a second tunable bandpass filter and means for coupling the first bandpass filter and the second bandpass filter to an antenna The method comprises the steps of tuning the first tunable bandpass filter to provide a passband corresponding to an assigned transmit frequency, and tuning the second tunable bandpass filter to provide a passband offset from an assigned receive frequency, when the duplexer is operated in a transmit mode When the duplexer is operated in a receive mode, the first tunable bandpass filter is tuned to provide a passband offset from an assigned transmit frequency and the second tunable bandpass filter is tuned to provide a passband corresponding to the assigned receive frequency

Method of channel frequency allocation for rf and microwave duplexers

A chassis-excited antenna apparatus, and methods of tuning and utilizing the same. In one embodiment, a distributed loop antenna configuration is used within a handheld mobile device (e.g., cellular telephone). The antenna comprises two radiating elements: one configured to operate in a high-frequency band, and the other in a low-frequency band. The two antenna elements are disposed on different side surfaces of the metal chassis of the portable device; e.g., on the opposing sides of the device enclosure. Each antenna component comprises a radiator and an insulating cover. The radiator is coupled to a device feed via a feed conductor and a ground point. A portion of the feed conductor is disposed with the radiator to facilitate forming of the coupled loop resonator structure.

Chassis-excited antenna apparatus and methods

An adjustable multi-band planar antenna especially applicable in mobile terminals. In one embodiment, the feed of the antenna is connected by a multiple-way switch to at least two alternative points of the radiator element. When the feed point is changed, the resonance frequencies and thus the operating bands of the antenna change. In addition to varying the basic dimensions of the antenna, the distance between one feed point to another and a possible short-circuit point in the radiator, the value of the series capacitance produced by a reactive circuit that is formed between the feed point and switch, and the distance between the ground plane and the radiator, are parameters that may affect the antenna design.

Adjustable multi-band antenna and methods

An antenna component (and antenna) with a dielectric substrate and a plurality of radiating antenna elements on the surface of the substrate. In one embodiment, the plurality comprises two (2) elements, each of them covering one of the opposite heads and part of the upper surface of the device. The upper surface between the elements comprises a slot. The lower edge of one of the antenna elements is galvanically coupled to the antenna feed conductor on a circuit board, and at another point to the ground plane, while the lower edge of the opposite antenna element, or the parasitic element, is galvanically coupled only to the ground plane. The parasitic element obtains its feed through the electromagnetic coupling over the slot, and both elements resonate at the operating frequency. Omni-directionality is also achieved. Losses associated with the substrate are low due to the simple field image in the substrate.

Antenna, component and methods

An adjustable multi-band planar antenna especially applicable in mobile terminals and a radio device. The adjusting circuit ( 430 ) of the antenna is galvanically connected to a point (X) of the radiator, where the circuit can affect the places of at least two operating bands. The adjusting circuit comprises a multi-pole switch ( 433 ), by which said radiator point can be connected to one of alternative transmission lines. For example, one of two transmission lines ( 434, 435 ) is open and another shorted. A discrete capacitor (C 2 ) can be located between the separate conductor of the transmission line and an output pole of the switch as an additive-tuning element. The adjusting circuit further comprises a LC circuit ( 432 ) between the radiator ( 320 ) and the switch. Among other things, the lengths of the transmission lines, the values of the discrete components and the distance between the antenna short-circuit point (G) and the adjusting circuit connecting point (X) are then variables from the point of view of the antenna adjusting. Such values are calculated for these variables that each of the antenna operation bands separately shifts to a desired other place when the switch state is changed. The space required for the adjusting circuit is relatively small, and a relatively high efficiency is achieved for the antenna despite of the use of a switch.

Adjustable multiband antenna and methods

A radio frequency filter has a band-pass type frequency response which is controllable in a manner such that the frequency response may be moved between the transmission frequency (TX') and reception frequency (RX') of associated radio equipment. Thus the radio frequency filter may be used both as a transmission filter and as receiving filter, provided that the transmission and reception take place at different times. The radio frequency filter includes a change-over switch, which connects the radio frequency filter to a transmitter when the pass band of the radio frequency filter is in the transmission frequency, and which connects to the receiver when the pass band of the radio frequency filter is in the reception frequency.

Jouni Ala-Kojola

Papers

Switchable duplex filter