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Worldwide, defense technologies are rapidly evolving and are currently aiming at integrating diverse functionalities like radar, electronic warfare, communications, on a singular miniaturised platform. Hence, it cannot be denied that the advancements in modern active phased array radar technologies assume a critical role towards the achievement of this goal. A typical active phased array radar comprises of an active antenna array unit (AAAU) consisting of a large number of radiating elements, transmit/receive (T/R) modules with other associated RF and digital circuitry and power electronics. This paper presents mainly the developments in transmit/receive (T/R) module technology, which assimilates various stages of the technological evolution -past, current and futuristic. It discusses how these technologies contribute towards the improvement of efficiency, miniaturisation and reliability without compromising its performance parameters.

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In the present work we report design, simulation, fabrication and characterization of thin film bulk acoustic resonator (FBAR). The FBAR has been modeled as a single port device with two terminals. The FBAR has been fabricated using Si-SiO2-Al–ZnO-Al structure. Zinc Oxide (ZnO) films were deposited by RF magnetron sputtering using Ceramic ZnO target in Ar-O2(1:1) ambient without external substrate heating. The XRD result confirms the preferred C-axis orientation of the films required for good piezoelectric properties. These ZnO films have been used to fabricate air gap type resonator. A four mask process sequence was used for this purpose. Lift-off process was used to pattern Al top electrode. In order to create the air cavity under the active device area, the bulk Si was etched in 40 % KOH at 80 °C. A specially designed mechanical jig was used to protect the front side of the device during anisotropic etching. Vector network analyzer was used to measure the reflection coefficient (S11: Return Loss) of the device. The resonant frequency of the resonator was measured to be 2.89 GHz as compare to the simulated frequency of 2.85 GHz with a return loss of 14.51 dB.

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