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Finger-Fitts law [6] is a variant of Fitts’ law which accounts for the finger ambiguity in touch pointing. In this paper we investigated two research questions related to Finger-Fitts law: (1) Should Finger-Fitts law use nominal target width W or effect target width We to model MT? and (2) should Finger-Fitts law use a pre-defined value (denoted by σa) or a free parameter (denoted by c) to represent the absolute ambiguity caused by finger touch? Our investigation on two touch pointing datasets showed that there are cases where using nominal width has stronger model fitness, and also cases where using effective width is better. Regarding the representation of finger ambiguity, using a free parameter c to represent the ambiguity of finger touch always leads to stronger model fitness than using the pre-defined σa, after controlling for overfitting. It indicates that viewing the finger ambiguity as an empirically determined parameter has more flexibility to capture the ambiguity of finger touch involved in the study. Overall, our research advances the understanding on how to model Finger touch input with Finger-Fitts law. 

A 28-GHz one-bit direct-detection based MIMO receiver with wireless LO distribution is presented. Unlike a conventional MIMO structure, in this work the antenna receives both RF and the broadcast single-ended LO, and directly converts them to an IF signal by using a simple low-power square-law detector without the need for a conventional mixer or LO buffers. An LNA with a notch filter is designed to help reduce the non-idealities that appear when the input LO power is lower than that of the RF. A 1-GS/s symbol rate with a high error-vector magnitude is achieved with a power consumption of 33 mW by using a 0.18um SiGe BiCMOS process.