Low-distortion, low-loss varactor-based adaptive matching networks, implemented in a silicon-on-glass technology

RF Technology Enablers for Software-Defined Radios

“…This technology provides a low loss substrate and patterning of both the front and back sides of the wafer so the intrinsic varactor can be directly contacted by thick metal on both sides [19]. This eliminates the need for a buried layer or finger structures.…”

“…6. The measured Q of varactor structures realized in this technology (using a uniform doping of 1 × 10 17 cm −3 ) varied from 100 to 600 as the bias voltage changed, due the decreasing length of the undepleted region at larger reverse bias voltages [19]. RF tuners have been implemented in this technology, where the impedance points cover the range from 0.2 to 82 ohm, yielding a VSWR > 250 : 1.…”

Enabling Low-Distortion Varactors for Adaptive Transmitters

“…In order to overcome these drawbacks, varactor diode-based circuit topologies-along with a high performance silicon-onglass varactor diode process technology-have been presented [9], [10]. These proposed varactor configurations can act as variable capacitors with ideally zero or extremely low distortion [9]- [15].…”

Thin fim barium strontium titanate capacitors for tunable RF frond-end applications

“…The loss is modeled by interconnect and electrode losses (R e ), the resistance of the semiconductor material R semi and by a capacitor (see Figure 2.1b). R e can be minimized by using thick metals and substrate-transfer techniques [16]. R semi is obtained by integrating ρ(x) from h vc,min to the backside electrode.…”