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Frequency diverse arrays (FDA) are recently introduced. Not only the phased array and frequency scanning arrays, but also FDA provides electronic beam scanning ability. Moreover, electronic beam scanning is provided without the use of phase shifters or vector modulators. Nevertheless, reported studies on this concept do not provide practically implementable results. In this paper, fundamental expressions of the FDA operation and its typical implementation schemes are reviewed, and an ultimately useful scheme for implementing and FDA is introduced based on linear frequency modulated continuous waveform (LFMCW). The mathematical foundations of LFMCW FDA are developed and used to design a basic proof of concept structure. This structure is also implemented and the measurements related to the implementation are presented with discussions on the results. [ABSTRACT FROM PUBLISHER]

We present the results on the correlation between the flux to voltage transfer function, Vspp, of the rf-SQUID and the rf-bias frequency as well as rf-bias power. Measurements were performed for different SQUID gradiometer samples chosen from the same batch or different batches. In order to have full control on the electronics parameters, an experimental rf-SQUID circuit was designed and implemented with an operation frequency of 600 MHz to 900 MHz. According to our findings, it has been observed that at any particular rf-bias power, Vspp vs. rf-bias frequency shows Sinc-like behavior. We observed that the main lobe maxima exist close to the resonance frequency of the LC tank circuit and by changing only the power, amplitude of the main lobe and side lobes can be controlled. The Vspp, vs. rf-bias power analysis shows that maximum of Vspp, strongly depends on the bias frequency. This can be correlated with the S11 parameter of LC tank circuit. We also observed that the devices from the same batch show main lobe maxima at different frequencies and/or power. Our SQUIDs with high working frequency gave their maxima at lower rf-bias powers leading to the need of having high frequency electronics with low bias power handling capabilities. It has also been observed that the SQUIDs from the same chip show similar characteristics regarding Vspp vs. frequency and power while the SQUIDs from different batches show completely different behavior for a fixed LC tank circuit configuration. [ABSTRACT FROM AUTHOR]