Because of the increase in new features, functionality and industrial design requirements, the space available for the mobile system antenna is shrinking at a rapid rate. As antennas are wrapped and repathed, they lose efficiency. Some of this lost performance can be recovered with antenna tuning, in which the system uses dynamic impedance tuning techniques to optimize the antenna performance for both the frequency of operation and the environmental conditions.

Mobile Cellular Antenna Tuning TechnologyOne of the most significant challenges facing the mobile handset designers is the poor antenna performance for multi-band multi-mode handsets. Dynamically tuning the antenna to compensate for the increasing bandwidth requirements and environmental effects will significantly improve the antenna performance. Further, as the market demands new wideband services in the handset, such DVB-H and ISDB-T for mobile TV, the use of antenna tuning becomes a necessity. Until now, no tunable element met the needs of the mobile products industry in power handling, reliability, high volume production and integration.

In addition to traditional cellular frequencies, today’s mobile phones may need to support frequencies from 0.7 GHz up to 2.7 GHz, for cellular bands as well as non-cellular services such as mobile TV, Bluetooth, WLAN and GPS. The RF transceiver of the mobile phone is designed for 50 Ohm impedance. Ideally, the antenna would match that impedance across the entire frequency band. However, small handsets have inherently narrow antenna bandwidth, poor antenna matching and low radiation efficiency, and, without antenna tuning, are ultimately are prone to antenna mismatch. To date, several first generation open-loop antenna tuning systems are being used in handsets, and development teams are beginning to design adaptive closed-loop antenna tuning systems. Micro-electromechanical systems (MEMS) and ferroelectric materials technologies (such as BST) have been used to implement tunable antennas and filters, however they are not yet proven for high-volume production and both typically require a high bias voltage (up to 30V or higher) to tune, requiring a separate CMOS charge pump and controller chip.

Peregrine’s DuNE Technology is the key to unlocking the future of digital tunability in mobile RF systems. The first devices in the DuNE DTC portfolio are designed to meet the stringent broadband requirements for DVB-H and ISDB-T mobile TV; multi-mode, multi-band GSM/WCDMA cellular handsets; and the power handling requirements for interoperability between the two applications. Because UltraCMOS technology enables monolithic integration of RF, analog and digital circuitry, Peregrine’s single-die DuNE DTCs integrate high-Q tunable capacitors (Q=40 to 80 at 1-2 GHz) with a built-in low-voltage serial interface , in a chip-scale package.