A high power handling capability CMOS T/R switch for x-band phased array antenna systems

This paper presents a single-pole double-throw (SPDT) transmit/receive (T/R) switch fabricated in 0.25-μm SiGe BiCMOS process for X-Band (8 – 12 GHz) phased array radar applications. The switch is based on series-shunt topology with combination of techniques to improve insertion loss (IL), isolation and power handling capability (P1dB). These techniques include optimization of transistor widths for lower insertion loss and parallel resonance technique to improve isolation. In addition, DC biasing of input and output ports, on-chip impedance transformation networks (ITN) and resistive body-floating are used to improve P1dB of the switch. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 30.8 dB and P1dB of 28.2 dBm at 10 GHz. The return losses at both input and output ports are better than 16 dB from 8 to 12 GHz. To our knowledge, this work presents the highest P1dB at X-Band compared to other reported single-ended CMOS T/R switches in the literature

A new resonant circuit for 2.45 GHz LC VCO with linear frequency tuning

A new MOS varactor bank is proposed to implement a 2.45 GHz SiGe BiCMOS LC-tank voltage controlled oscillator (VCO) with linear frequency tuning. Compared to a conventional VCO, the proposed technique improves the quality factor of the LC-tank while preserving the linearity of the circuit. Realized in 0.25-μm SiGe BiCMOS technology, VCO exhibits 35% VCO gain (KVCO) variation from 2.29 to 2.66 GHz with a 16% tuning ratio. The VCO also exhibits a phase noise of -113 dBc/Hz at 1 MHz offset frequency and consumes 1.7 mA from 1.8 V supply

Capacitance to voltage converter design for biosensor applications

Due to advances in MEMS fabrication, Lab-on-Chip (LoC) technology gained great progress. LoC refers to small chips that might do similar works to equipped laboratory. Miniaturization of laboratory platform results in low area, low sampleconsumption and less measurement time. Hence, LoC with IC integration finds numerous implementations in biomedical applications. Electrochemical biosensors are preferred for LoC applications because electrochemical biosensors can be easily integrated into IC designs due to electrode-based transducing. Capacitive biosensors are distinctive in electrochemical biosensors because of their reliability and sensitivity advantages. Therefore Interdigitated electrode (IDE) capacitor based biosensor system is preferred for development of biosensor platform. In this thesis, capacitive biosensor system with new Capacitance to Voltage Converter (CVC) designs for LoC applications is presented. Multiple IDE capacitor sensing and varactor-based compensation are new ideas that are presented in this thesis. Proposed system consists of five blocks; IDE Capacitor based tranducer, CVC, Low-Pass Filter, Linear LC-Tank Voltage Controlled Oscillator (VCO) and Class-E Power Amplifier (PA). System building blocks are designed and fabricated using IHP's 0.25 µm SiGe BiCMOS process because of its advantage at high frequency and post-process that IHP offers. Varactor tunable CVC design provides highly linear relationship between output voltage and capacitance change in sensing capacitor. Varactor is used in reference capacitor to compensate changes in sensing capacitor. Total chip area is 0.4 mm2 including pads. 10 MHz operating frequency is achieved. Total power consumption changes between 441 µW and 1,037 mW depending on the sensor capacitance

A fully integrated multiband frequency synthesizer for WLAN and WiMAX applications

This paper presents a fractional N frequency synthesizer which covers WLAN and WiMAX frequencies on a single chip. The synthesizer is fully integrated in 0.35μm BiCMOS AMS technology except crystal oscillator. The synthesizer operates at four frequency bands (3.101-3.352GHz, 3.379-3.727GHz, 3.7-4.2GHz, 4.5-5.321GHz) to provide the specifications of 802.16 and 802.11 a/b/g/y. A single on-chip LC - Gm based VCO is implemented as the core of this synthesizer. Different frequency bands are selected via capacitance switching and fine tuning is done using varactor for each of these bands. A bandgap reference circuit is implemented inside of this charge pump block to generate temperature and power supply independent reference currents. Simulated settling time is around 10μsec. Total power consumption is measured to be 118.6mW without pad driving output buffers from a 3.3V supply. The phase noise of the oscillator is lower than -116.4dbc/Hz for all bands. The circuit occupies 2.784 mm2 on Si substrate, including DC, Digital and RF pads

A new lab-on-chip transmitter for the detection of proteins using RNA aptamers

A new RNA aptamer based affinity biosensor for CReactive Protein (CRP), a risk marker for cardiovascular disease was developed using interdigitated capacitor (IDC), integrated in Voltage Controlled Oscillator (VCO) and output signal is amplified using Single Stage Power Amplifier (PA) for transmitting signal to receiver at Industrial, Scientific and Medical (ISM) band. The Lab-on-Chip transmitter design includes IDC, VCO and PA. The design was implemented in IHP 0.25μm SiGe BiCMOS process; post-CMOS process was utilized to increase the sensitivity of biosensor. The CRP was incubated between or on interdigitated electrodes and the changes in capacitance of IDC occurred. In blank measurements, the oscillation frequency was 2.464GHz whereas after RNA aptamers were immobilized on open aluminum areas of IDC and followed by binding reaction processed with 500pg/ml CRP solution, the capacitance shifted to 2.428GHz. Phase noise is changed from -114.3dBc/Hz to -116.5dBc/Hz