Grzegorz Szczepkowski

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— Transmitter leakage is caused by limited isolation between Tx and Rx paths of an frequency-division duplexing (FDD) transceiver due to use of non-ideal duplexers. As the leakage can seriously impair the performance of the receiver, it is important to increase the isolation of the existing system. A portion of the leakage falling into the Rx band can't be(More)
This paper presents a wideband voltage controlled oscillator topology based on an active inductor generating negative resistance. The proposed architecture covers a frequency band between 1.325 GHz - 2.15 GHz with average in-band phase noise of -86 dBc/Hz at 1 MHz offset from the carrier frequency. Power consumption of the oscillator core is 28 mW from a(More)
—This paper presents a high precision wide band switched delay line with fine tuning capability and low insertion loss. The circuit is designed to operate in the frequency range from 1 GHz to 5 GHz and tuned using MEMS switches targeting a minimum delay step of 7 ps. The delay line uses a single layer of a high permittivity substrate (ε r =10), and the MEMS(More)
— This paper presents a study on the effect of impedance mismatch on phase linearity (group delay variations) in grounded coplanar waveguide (GCPW) structures. Two 400 ps GCPW delay lines were designed using a short circuited stub and a transmission line. The structures were simulated over a wide frequency range (0.1 GHz-5 GHz) using both ADS circuit model(More)
This paper presents a compensation method of active inductor losses, employing passive gyrator degeneration rather than an external negative impedance converter. Theoretical analysis is confirmed by a comparative simulations of two resonators designed for 434 MHz band, using Eldo RF and Spectre and the UMC 0.18 μm 1P6M process. Presented results show(More)
—In an Frequency-Division Duplexing (FDD) transceiver, a high power transmitted signal can leak into the RX chain due to limited isolation of a duplexer. Such signal is known as TX leakage and can seriously affect the performance of the receiver. A transmitter leakage canceller structure is proposed in this paper in order to improve isolation between the(More)
This paper presents a study of linearity in wideband CMOS low noise amplifiers (LNA) and its relationship to power consumption in context of Long Term Evolution (LTE) systems and its future developments. Using proposed figure of merit (FoM) to compare 35 state-of-the-art LNA circuits published over the last decade, the paper explores a dependence between(More)
— This paper presents a new consistent analysis of self-oscillating active in-ductors together with a complete design example of a 90 nm CMOS current controlled oscillator (CCO) for ISM applications. Using the proposed passive compensation method in place of a standard negative impedance converter, typical performance of active induc-tor oscillator is(More)
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