This paper presents a wideband low-noise amplifier (LNA) designed to be used as the first stage of the receiver in the Square Kilometer Array radio telescope. The LNA design procedure and its layout features are discussed. The noise figure optimization procedure determines the signal-source resistance that results in reduced noise figure. When used in the radio telescope, the required signal-source resistance will be presented by the telescope custom-made antenna elements. The LNA, designed in 90 nm bulk CMOS, achieves sub-0.2 dB noise figure from 800 MHz to 1400 MHz, return loss of more than 11 dB, gain of more than 17 dB driven into a 50 load, output 1 dB compression point of 2 dBm, output IP3 of 12 dBm, and output IP2 of 22 dBm while consuming 43 mA from a 1 V supply. In the LNA implementation presented in this paper the load choke inductor and the source inductor are integrated whereas the gate-, bias-, and the choke-inductor between two transistors of the cascode are external. The noise figure of the presented LNA is to our knowledge the lowest noise figure achieved by a power matched wideband CMOS LNA at room temperature.

Sub-0.2 dB Noise Figure Wideband Room-Temperature CMOS LNA With Non-50 $\Omega$ Signal-Source Impedance

A 1.5 V, 3/spl sim/11 GHz CMOS UWB LNA using dual feedback loops is reported. Using shunt capacitive feedback and series transformer feedback the broadband matching condition is achieved with high flat gain. Fabricated in 0.18 /spl mu/m CMOS process, the measurement result demonstrates power gain of 11 dB and maximum NF less than 5.6 dB throughout the frequency range from 3.1 to 10.6 GHz with power consumption of 10.6 mW.

3/spl sim/11-GHz CMOS UWB LNA using dual feedback for broadband matching

This paper presents the development of a wide-band amplifier with matched input impedance and low noise temperature over 10-20 GHz. Here, the novel wide-band feedback mechanism provided by the transistor's intrinsic gate-drain capacitor will be analyzed in detail with both the derived input reflection coefficient and noise temperature of the resulting circuit confirmed by their simulated counterparts. It is thus clear why by fine tuning its output RC loading impedance and source inductance, a transistor's input reflection coefficient and noise temperature can be greatly improved over broad bandwidth. To demonstrate the feasibility of this novel approach, a wide-band low-noise amplifier (LNA) is designed and characterized. A bandwidth broadening mechanism using double feedback is also proposed for the future design of matched ultra-wide-band LNA.

https://ir.nctu.edu.tw:443/bitstream/11536/12527/1/000236081500036.pdf

Wide-band matched LNA design using transistor's intrinsic gate-drain capacitor

Researchers have described the concept of noise matching since at least the 1950s [1]-[4], with studies demonstrating the interrelationships among the noise factor of a low-noise amplifier (LNA), the LNA's noise parameters, and the signal-source impedance Zs. Noise matching is accomplished when an LNA is driven by a signal source, the impedance (or admittance) of which is designed-perhaps using a matching network-to equal the LNA's optimum signal-source impedance for minimum noise, or Zopt. The complex Zopt = Gopt + jXopt represents two of the four noise parameters that completely characterize the noise behavior of a linear two-port device, such as an LNA. The other two noise parameters are the minimum noise factor, Fmin , and the Lange invariant N [5], [6], which is, arguably, a more fundamental parameter than the often-used equivalent noise resistance, Rn.

No Noise Is Good Noise: Noise Matching, Noise Canceling, and Maybe a Bit of Both for Wide-Band LNAs

This invention relates to a low noise amplifier, used in radio frequency integrated circuit design, especially low noise amplifiers for ultra broad-band wireless communication, comprising at least a transistor of the core circuit of a low noise amplifier structure, a transformer that is implemented on the chip, in order to form a dual feedback amplifier, that is, an amplifier structure comprising an inductive feedback and a capacitive feedback, wherein the capacitive feedback is used for the low and medium frequency range, while the inductive feedback is used for the high frequency range. By assembling an amplifier circuit with these two feedback paths, it is possible to provide a broadband and good impedance matching at the signal input end of the circuit. The low noise amplifier circuit structure of the present invention is able to provide optimal conditions for broadband input impedance matching and broadband noise optimum; besides significantly increasing the gain and gain flatness, there are also huge improvements to the noise performance and the cost-down on fabrication, and the energy consumption can also be maintained at a very low level.

https://ir.nctu.edu.tw:443/bitstream/11536/105643/1/20070176686.pdf

Ultra broad-band low noise amplifier utilizing dual feedback technique

This paper analyzes different input-matching mechanisms used in designing the wide-band amplifiers in general, and the low noise amplifiers (LNA) in particular, and their corresponding noise impact. Among them, the most promising one is the reactive-feedback circuit configuration, which is a combination of high-frequency inductive feedback and low frequency capacitive feedback. In this paper the simulated result that both matched input impedance and low noise temperature Tn can be achieved simultaneously over a wide bandwidth in the single-ended low noise amplifier is proved mathematically and is well interpreted. This understanding of reactive feedback is crucial for the future development of ultra-wide-band low-noise amplifiers.

https://ir.nctu.edu.tw:443/bitstream/11536/24009/1/000227352500007.pdf

Mark S. C. Yang

Papers

Investigation of Different Input-Matching Mechanisms Used in Wide-Band LNA Design