Abdullah Alburaikan

Low Phase Noise Free-Running Oscillator Based on High Selectivity Bandpass Filter Using Composite Right/Left-Handed Transmission Line

This letter presents a novel low phase noise freerunning oscillator based on a high selectivity bandpass filter (BPF) using a composite right/left-handed transmission line (CRLH TL). The oscillator is designed at the spectrum-based quality factor (Qs) peak frequency to achieve low phase noise performance. Ata center frequency of 2.05 GHz, the oscillator demonstrates, experimentally, a phase noise of -150.4 dBc/Hz at 1 MHz frequency, offset with a figure of merit(FOM) of -207.2 dBc/Hz, less than -32 dBm spurious harmonics, and total oscillator power consumption of 6.1 mW from a 2 V supply voltage.

Low-Power and Wideband LC-VCO for WiMAX in CMOS Technology

This work presents an ultralow phase-noise and wide turning-range voltage-controlled oscillator (VCO) for 5.72GHz WiMAX applications. The fully integrated VCO is designed and simulated using 130-nm CMOS technology. Instead of using the conventional diode-based varactor in the tank design, high-performance body-grounded NMOS transistors are employed as effective varactors. A controlled self-biasing current source is implemented to avoid higher power supply sensitivity and higher up-conversion of flicker noise. The proposed VCO-measured results demonstrate a worst case phase noise of -132.68dBc/Hz at 1MHz frequency offset with an excellent figure of merit (FOM), which is -201.6dBc/Hz under a power consumption of 2.21mW. The VCO shows a tuning range of approximately 37.59%.

Miniaturized dual-wideband bandpass filter using coupled slotted open stubs

This paper presents the design of a super-compact dual-wideband bandpass filter (BPF) using quarter-wavelength slotted open-circuited stubs (SOSs). These slotted open stubs are used to define the second and the third stopbands at 3 and 9 GHz respectively. Both stubs are separated by quarter-wavelength impedance transformers. Unlike conventional quarter-wavelength impedance transformers, this filter has a high-pass meandered line that is shorted to ground to form an additional stopband at zero frequency. Using this approach, a dual-wideband bandpass filter is designed, fabricated and measured. The measured results show that the fabricated dual-wideband BPF has two passbands with a fractional bandwidth of 117% and 36%, at respective center frequencies of 1 GHz and 6.65 GHz. The filter has a compact size (0.09 λg × 0.05 λg) and exhibits an attenuation level greater than 20 dB up to 12 GHz.

High selectivity microstrip bandpass filter using feedback CRLH-TL unit cell

A new and simple approach to design high selectivity microstrip bandpass filter (BPF) is reported. Based on the signal interference concept, the selectivity of a BPF using composite right/left handed transmission line (CRLH TL) unit cell is significantly improved. Thus, by employing a single coupled line section and CRLH TL unit cell in the feedback, a bandpass filter with high selectivity, multiple transmission zeros (TZs) within the upper stopband and low insertion loss can be realized. The simulation results show that the proposed BPF has a fractional bandwidth of 8% centred at 2.4 GHz with high roll-off rate of 300 dB/GHz.

Miniaturized via-less ultra-wideband bandpass filter based on CRLH-TL unit cell

In this paper, a new via-less ultra-wideband (UWB) bandpass filter design based on a composite right/left-handed transmission line (CRLH-TL) unit cell is presented. Microstrip capacitive patch is used to provide virtual ground and replace the via in the conventional CRLH TL. Via fabrication complexity can be avoided for large-scale and cost-effective production by using microstrip patch. By cascading the interdigital coupled line with a low-pass filter (LPF) based on symmetrical split ring resonator (SSRR) defected ground structure (DGS), an UWB frequency response is achieved. SSRR DGS was used to obtain wider upper-stopband and sharp roll-off rate. The filter has compact size (15.6 × 13 mm2) and exhibits a rejection level greater than 20 dB at both upper and lower stopband. The filter has an insertion loss of 0.9 dB, a return loss better than 14 dB, and a fractional bandwidth of more than 100% at center frequency of 6.8 GHz.

Wide tuning range voltage controlled oscillator (VCO) with minimized phase noise variation in nanoscale CMOS technology

A cross-coupled differential VCO with low phase noise variation is presented. The VCO core adopts a metal-oxide-metal (MOM) digital switching capacitor array (DSCA), which is connected in series and in parallel to the nMOS varactor in order to reduce the KVCO variation. For further gain linearity, wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to three nMOS varactor pairs. Each pair is biased at a different voltage. The proposed VCO has been designed and implemented in UMC 130-nm, 6-metal CMOS technology and operates from 3.45 GHz to 6.23 GHz with 55.6% tuning range, phase noise variations ranging between -134 dBc/Hz and -130.8 dBc/Hz and power consumption below 6 mW at supply voltage of 3.2 V. The simulated phase noise at 1 MHz offset is 132.4 dBc/Hz at 5.0 GHz and a good FOM performance of approximately 204.5 dBc/Hz is achieved.

Low-phase noise variation VCO implementing resistorless digitally controlled varactor

A novel resistorless digital capacitor switching array (DCSA) has been implemented into a wideband CMOS VCO for 5-GHz WiMAX/WLAN applications. The proposed DCSA is added both in series and parallel to nMOS varactors. Based on this, a wideband VCO is achieved, which not only exhibits lower phase noise in comparison with reported state-of the-art wideband VCOs, but also has low phase noise variation of less than 5 dBc/Hz. In addition, it has demonstrated low power consumption, improved linearity of the f-V curve and extended tuning range. The proposed VCO has been designed using UMC 130 nm CMOS technology. It operates from 3.65 GHz to 6.34 GHz, with a phase noise of -132.70 dBc/Hz at 1 MHz offset, a figure of merit (FoM) of -202.9 dBc/Hz, less than -41 dBm spurious harmonics and total VCO core power consumption of 2.88 mW from a 3.2 V supply voltage.