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A wirelessly powered and controlled implantable device capable of locomotion in a fluid medium is presented. Two scalable low-power propulsion methods are described that achieve roughly an order of magnitude better performance than existing methods in terms of thrust conversion efficiency. The wireless prototype occupies 0.6 mm × 1 mm in 65 nm CMOS with an external 2 mm × 2 mm receive antenna. The IC consists of a matching network, a rectifier, a bandgap reference, a regulator, a demodulator, a digital controller, and high-current drivers that interface directly with the propulsion system. It receives 500 μW from a 2 W 1.86 GHz power signal at a distance of 5 cm. Asynchronous pulse-width modulation on the carrier allows for data rates from 2.5-25 Mbps with energy efficiency of 0.5 pJ/b at 10 Mbps. The received data configures the propulsion system drivers, which are capable of driving up to 2 mA at 0.2 V and can achieve speed of 0.53 cm/sec in a 0.06 T magnetic field.

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A wirelessly powered 11 μW transceiver for implantable devices has been designed and demonstrated through 35 mm of porcine heart tissue. The prototype was implemented in 65 nm CMOS occupying 1 mm × 1 mm with a 2 mm × 2 mm off-chip antenna. The IC consists of a rectifier, regulator, demodulator, modulator, controller, and sensor interface. The forward link transfers power and data on a 1.32 GHz carrier using low-depth ASK modulation that minimizes impact on power delivery and achieves from 4 to 20 Mbps with 0.3 pJ/bit at 4 Mbps. The backscattering link modulates the antenna impedance with a configurable load for operation in diverse biological environments and achieves up to 2 Mbps at 0.7 pJ/bit. The device supports TDMA, allowing for operation of multiple devices from a single external transceiver.

Accurate estimation of signal direction of arrival The eigen-analysis method based on temporal (DOA) has many applications in communication and radar averaging has been investigated by many authors in the systems. For example, in defense application, it is past [2]. However, temporal averaging requires average important to identify the direction of possible threat. One over multiple time samples to estimate the covariance example of commercial application is to identify the matrix. Sometimes, the radar system prefers to have an direction of emergency cell phone call such that the rescue estimated covariance in a single snapshot. We propose team can be dispatched to the proper location.eigen-analysis based on spatial smoothing so that we can DOA estimation using a fixed antenna has many have estimated covariance in a single snapshot.limitations. Its resolution is limited by the mainlobe Performances based on several different spatial averages beamwidth of the antenna. Antenna mainlobe beamwidth is are discussed in this paper.inversely proportional to its physical size. Improving the Extensive computer simulations are used to verify the accuracy of angle measurement by increasing the physical processing algorithms. For narrowband signals, both aperture of the receiving antenna is not always a good processing algorithms provide enhanced resolution and option. Certain systems such as a missile seeker or aircraft have ability to resolve multiple targets as long as the antenna have physical size limitations; therefore, they have number of targets is less than the system's degree of relatively wide mainlobe beamwidth. Consequently, the freedom. SMI provides better performance than the LMS resolution is quite poor. Also, if there are multiple signals method due to the fact that this method is relatively falling in the antenna mainlobe, it will be difficult to immune to excessive mean square error. However, for distinguish them. multiple wideband waveforms, sometimes the array antenna has difficulty to resolve them, especially if signals Instead of using a filxed antenna, an array antenna arimignthateawtharospilsprto.system with innovative signal processing would enhance the are ipingin tanb tennitna stial atin.signal~~~. DO. It alohsteailt oietf This problem can be solved by extending the array antenna resolution of signal DOA.It also has theabilitytoidentifyto a space time adaptive processor (STAP) [3]. STAP is multiple targets. Two types of signal processing methods, model based and eigen-analysis estimation techniques, are basically replacing the sngle weilght at the output of each presented in this paper. array element by an adaptive filter.The model based approach models the observed data Statistical analysis of the performance of the processing as the output of a linear shift invariant system driven by algorithms and processing resource requirements are zero mean white noise. The signal's DOA can be estimated discussed in this paper. by evaluating the model parameters. This approach has properties similar to the ma...