Hardware Implementation Overhead of Switchable Matching Networks

Nowadays, more and more RF systems include switchable matching networks to decrease the impact of the environment-dependent antenna impedance on the RF front end performance. This paper reviews the theoretical lower limit on the required number of matching states to match VSWR ranges and then presents an analysis of hardware implementations to...

Beamformer with constant-Gm vector modulators and its spatial intermodulation distortion

Spatial interference rejection in analog adaptive beamforming receivers can improve the distortion performance of the circuits following the beamforming network, but is susceptible to the nonlinearity of the beamforming network itself. This paper presents an analysis of intermodulation product cancellation in analog active phased array receivers...

An 8-10 GHz upconversion mixer, with a low-frequency calibration loop resulting in better than -73dBc in-band spurs

An 8-10 GHz X-band upconversion quadrature mixer stage implemented in 250 nm SiGe BiCMOS is presented. Orthogonality of the spurious responses caused by clock feed through, I/Q mismatch and baseband harmonics after self-mixing was exploited to realize a baseband calibration scheme reducing all in-band spurs down to below -73dBc, for baseband...

Integrated Dual-Channel X-Band Offset-Transmitter for Phase Steering and DDMA Arrays

Multiple-Input and Multiple-Output (MIMO) arrays provide more degrees of freedom than conventional phased arrays. They require that every transmitting element of the array can be identified when received. One way to achieve this is to give every element its own unique frequency. Offset-transmitters may be used to introduce MIMO or Doppler...

Analysis of the signal transfer and folding in N-path filters with a series inductance

N-path filters exploiting switched-series-R-C networks can realize high-Q blocking-tolerant band-pass filters. Moreover, their center frequency is flexibly programmable by a digital clock. Unfortunately, the time variant nature of these circuits also results in unwanted signal folding. This paper proves analytically that folding can be reduced...

On the minimum number of states for switchable matching networks

The impedance of an antenna changes heavily with changing EM environments, while RF power amplifiers (PAs) are optimized for driving a well-defined load impedance. As a solution, switchable matching networks are used in automatic antenna tuners to match the antenna impedance to (about) the desired PA load impedance. This paper presents a...

3.5 A 1.0-to-2.5GHz beamforming receiver with constant-Gm vector modulator consuming < 9mW per antenna element in 65nm CMOS

Beamforming phased-array receivers aim to increase receiver sensitivity and reject interferers in the spatial domain [1,2]. A receiver with programmable phase shift and high linearity is crucial to cope with interference. Switched-capacitor vector modulators can provide adequate phase shift and linearity [3,4], but so far, at the cost of a high...

Multi-band linear chirp generation based on a type-III PLL

A type-III PLL is used to generate linear frequency ramps with 386 kHz RMS frequency error in L-band (3088 kHz in X-band) and 10% fractional bandwidth. Pulse durations can be as low as 10 μs without performance degradation. The system covers the L-, S-, C- and X-bands. A programmable output driver delivering -17.9 to +4.9 dBm differentially is...

A multi-band, high bandwidth, short duration linear chirp generation IC for phased-array applications

This work presents a fully integrated multi-band frequency synthesizer that is capable of creating wide-band linear frequency sweeps of very short duration. The main aim is to create a flexible waveform generation system, requiring distribution of a low frequency reference rather than RF signals. By using a phase-locked loop, frequency...

Advance in silicon phased-array receiver IC's

Phased-Arrays are increasingly used, and require Silicon implementations to result in affordable multi-beam systems. In this paper, CMOS implementations of two novel analogue beamforming multi-channel receivers will be presented. A narrow-band highly linear system exploiting switches and capacitors in advanced CMOS is presented, implementing a...

A 1.5-to-5.0GHz input-matched +2dBm P1dB all-passive switched-capacitor beamforming receiver front-end in 65nm CMOS

Phased arrays in CMOS for consumer communication bands aim to enhance receiver performance by exploiting beamforming with antenna arrays. Sensitivity increases with the number of antenna elements through array gain and interferers can be cancelled through the spatial filtering of the beam pattern [1]. For the latter, the linearity of the...

A 1.0-to-4.0GHz 65nm CMOS four-element beamforming receiver using a switched-capacitor vector modulator with approximate sine weighting via charge redistribution

Phased-array receivers provide two major benefits over single-antenna receivers [1]. Their signal-to-noise ratio (SNR) doubles for each doubling in the number of elements, resulting in extended range. Secondly, interferers can be rejected in the spatial domain for increased link robustness. These arrays can be implemented by phase shifting and...

Phased-Array Antenna Beam Squinting Related to Frequency Dependency of Delay Circuits

Practical time delay circuits do not have a perfectly linear phase-frequency characteristic. When these delay circuits are applied in a phased-array system, this frequency dependency shows up as a frequency dependent beam direction (“beam squinting”). This paper quantifies beam squinting for a linear one-dimensional phased array with equally...

Unified Frequency-Domain Analysis of Switched-Series-RC Passive Mixers and Samplers

A wide variety of voltage mixers and samplers are implemented with similar circuits employing switches, resistors, and capacitors. Restrictions on duty cycle, bandwidth, or output frequency are commonly used to obtain an analytical expression for the response of these circuits. This paper derives unified expressions without these restrictions....