Abstract
We designed a reconfigurable dual-band reflection amplifier with operation frequency bands over 1.8 GHz and/or 2.4 GHz. This one-port amplifier boosts the reflected signal over either of these two frequency bands or both as a dual-band reflection amplifier. The amplifier circuit consists of an FET transistor and two p-i-n diodes, which act as switches to form a reconfigurable system. The measured reflection gains at single 1.8 GHz and 2.4 GHz frequency bands are 17.6 dB and 16.75 dB, respectively. The dual-band operation frequency shows 11.2 dB and 15 dB gain at 1.8 GHz and 2.4 GHz, respectively. Then, we realized a bidirectional amplifier using a dual-band −3 dB 90° branch line coupler integrated with two of the proposed reconfigurable reflection amplifiers. This bidirectional amplifier is a two-port bilateral amplifier. The measured reflection gains show at least 10 dB transmission gains ( ${S} _{21}$ and ${S} _{12}$ ) at operation frequency bands. The proposed reconfigurable bidirectional amplifier is then used in a dual-band Van Atta array. The proposed active retrodirective system outperformed passive Van Atta array by 5 dB gain with only half the number of antenna elements. Each component is investigated analytically and analyzed by advanced design system. Fabricated circuits are measured and show good agreement with simulations.
Highlights
B ACK-SCATTER Communications (BSC) are based on the reflection of electromagnetic waves
The results show that our system with two elements re-scatters the incoming field with higher strength compared to a four-element passive Van Atta array with the same dual band antenna elements in each frequency band
Recalling that the active Van Atta array contains dual band reflection amplifiers that can operate either in single band mode or in dual band mode, we examine the Radar Cross-Section (RCS) for both modes and refer to the single band mode as active Van Atta 1 and to the dual band mode as active Van Atta 2
Summary
B ACK-SCATTER Communications (BSC) are based on the reflection of electromagnetic waves. This negative input resistance can be implemented by transistors [8], [14], Gunn diodes [17] or tunnel diodes [15] These reflection amplifiers are designed to operate in one single frequency band. All proposed reflection amplifiers and active Van Atta arrays have been designed for a single frequency band. We propose a novel reconfigurable dual band active Van Atta array that increases the range and reduces the interference in BSC systems. We design a reconfigurable dual band active Van Atta array by using the proposed bidirectional. The proposed active Van Atta array shows 5 dB higher back-scattered field level on average for the both frequency bands, compared to a passive one with the double number of elements.
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