Small-Size X-Band Active Integrated Antenna With Feedback Loop

• Published in: IEEE transactions on antennas and propagation Vol. 56; no. 5; pp. 1236 - 1241
• Main Authors: Mueller, C.H., Lee, R.Q., Romanofsky, R.R., Kory, C.L., Lambert, K.M., Van Keuls, F.W., Miranda, F.A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Active integrated antenna (AIA); Antenna feeds; Antennas; Applied sciences; Battery; Design; Exact sciences and technology; Feedback; Feedback loop; FETs; Hafnium; High frequencies; Loaded antennas; microstrip; Microstrip antennas; National electric code; oscillator; Oscillators; phase noise; Radio frequencies; Radio frequency; Radiocommunications; Stable oscillations; Telecommunications; Telecommunications and information theory; Transmitting antennas; X-band; Phase noise; Performance evaluation; Active antenna; Radio wave; X band; Printed antenna; Frequency conversion; Centimetric wave; Directivity; Integrated antenna; Active integrated antenna (AIA); microstrip; Oscillator; Microstrip antennas; Radiation pattern; Radiated power; Permittivity
• DOI: 10.1109/TAP.2008.922628
• ISSN: 0018-926X

A small-sized active integrated antenna (AIA), consisting of a transmission feedback oscillator loaded with a microstrip antenna is presented in this paper. The oscillator antenna, which consists of a NEC super low noise high frequency field effect transistor (HF FET) integrated into the center of a segmented patch antenna, was designed for X-band at 8.50 GHz, and occupies a 5 times 6 mm 2 area. The active integrated antenna demonstrates stable oscillations and excellent radiation patterns at X-band design frequencies. When biased using a single 1.5 volt battery connected between the source and drain and with the gate terminal open, the antenna effective isotropic radiated power (EIRP) and direct current (DC)-to-radiated radio frequency (RF) conversion efficiency are +11.2 dBm and 10.5%, respectively. The radiated power level and directivity are +4.5 dBm and 6.7 dBi, respectively. The phase noise at 100 kHz offset from the carrier is -87.5 dBc/Hz, which is a notable improvement over existing AIA designs. The AIA features compact size and simple geometry, yet provides radiated power levels and radiation efficiencies that are comparable to values typically obtained using circuits that occupy larger areas, and use thicker substrates with much lower dielectric constant values.