Mehrdad Fahimnia

A 59–66 GHz Highly Stable Millimeter Wave Amplifier in 130 nm CMOS Technology

The design and fabrication of four-stage cascaded mm-wave low noise amplifiers (LNAs) in a 130 nm CMOS technology are presented. The simultaneous high stability factor and low noise figure are obtained using proper inductors in both gate and source of the transistor. Measured gain of 14.7 dB with a 7 GHz bandwidth has been achieved. The larger inductors are realized with microstrip lines to improve the performance of the LNA and minimize the circuit size.

Low Loss, Wideband, and Compact CPW-Based Phase Shifter for Millimeter-Wave Applications

This paper proposes a compact, low-loss, and low cost phase shifter for millimeter-wave phased array systems. The basic idea is to modify the propagation mode of a coplanar waveguide (CPW) by placing a high dielectric constant (40 <; εr <; 170) slab on top of it. The phase shift is varied by changing the air gap between the CPW line and the dielectric slab. A piezoelectric transducer has been used to control this air gap precisely. For fast but accurate modeling of the proposed phase shifter, two methods one based on spectral domain analysis and the other based on the conformal mapping have been developed and verified with full wave simulations and measurements. A prototype structure with the operational frequency range from 20 to 40 GHz is presented. The maximum phase shift obtained for the electrically controlled version at 40 GHz is 103 ° with loss variation of 0.2 dB. The total length is 2 mm.

An efficient method to design optimum millimeter wave low noise amplifier

Recent advancement in CMOS technology has created new opportunities to design low cost receivers for conventional and emerging millimeter wave applications. Short range communication, wireless personal area network (WPAN), car radar and mmw imaging are some examples of millimeter wave transceiver application which have been in the focus of many researchers [1–5].

WAVE ANALYSIS FOR INDUCTIVELY MATCHED MILLIMETER WAVE AMPLIFIER DESIGN

A new design approach based on wave analysis has been implemented in order to derive voltage gain, center frequency and bandwidth of millimeter wave amplifler using parameters of transmission lines (TL). The derived formula allow one to design high frequency amplifler with predetermined bandwidth and centner frequency. It has been shown that in the case of lossy TL or at high frequency, circuit theory cannot predict the amplifler gain behavior while presented wave theory can accurately predict the frequency response of the amplifler in both low and high frequency ranges.

Low insertion loss variable phase shifter for emerging millimeter-wave communication systems

This paper proposes a compact, low-loss, and low cost phase shifter for mmWave applications. The basic idea is perturbing the propagation constant of a CPW line by its loading with a high dielectric constant BLT ceramic. The phase shift is sensitive to the air gap between the CPW and the BLT sample. For a sample with a length of 3mm, a phase shift of 170° at 30GHz is obtained while the average insertion loss is less than 1.45dB with a variation of 1.1dB for the full range of phase shifts.

A 77 GHz controllable gain low noise amplifier

A 77 GHz low noise amplifier has been designed using common source topology implemented in low cost CMOS technology for various applications. A new method has been proposed for the design of the amplifier. In this method, input/output matching networks and transistor gate widths have been optimized for maximum gain and minimum noise figure. The design is flexible such that the LNA can operate in both high gain/high power and low gain/low power modes with low noise figure of less than 7 dB at 77 GHz. Amplifier gain is better than 18 dB consuming 60mW of dc power and it is better than 14.5 dB consuming 30 mW of dc power. The input and output return losses are better than 10 dB in the frequency range of 72 to 82 GHz.