A low band cellular terminal antenna impedance tuner in 130nm CMOS-SOI technology

Experimental Investigation of Adaptive Impedance Matching for a MIMO Terminal With CMOS-SOI Tuners

“…Hence, the MEMS process incurs high production cost, low volume capabilities and reliability issues [17]. Moreover, with the SOI process used in this work we can obtain improved RF performance over standard CMOS processes, especially in power handling and linearity [16]. The circuit schematic, printed circuit board (PCB) picture of the impedance tuner system, and capacitor bank circuit are shown in Figs.…”

“…In the context of the previous work, this paper makes the following contributions (see also Table 1):  RF design, evaluation and measurement of a complete AIM system based on a state-of-the-art tuner [16] custom-designed for a specific MIMO handset in a CMOS-SOI process applicable for mass production.  First of its kind practical verification of an AIM system in realistic propagation conditions and user scenarios probing the applicability of AIM in real systems with existing low-cost technologies.…”

“…The AIM tuner chip featuring programmable capacitors and digital control was designed in-house and fabricated by STMicroelectronics using their 130 nm CMOS-SOI process [16]. It is noted that even though micro-electro-mechanical systems (MEMS) outperform CMOS in power handling and loss characteristics, the MEMS process is not as mature as CMOS.…”

“…The system was designed as a double -network and it comprised three programmable capacitors (C1, C2 and C3), two off-chip inductors (L1 = L2 = 7.4 nH), decoupling capacitors and RF chokes. The chip includes three identical 5-bit programmable capacitors with digital control [16] with a total chip area of 0.8 x 2 mm 2 . The PCB area is 10 x 15 mm 2 .…”

“…The PCB area is 10 x 15 mm 2 . Figure 1(c) shows the capacitor bank circuit where R = 275 kΩ is the gate resistor, C = 190 fF is the custom designed capacitor, VC indicates the control voltage and W1-W8 indicates the transistors used for the digital control [16].…”