Sun, 06 Jul 2008 11:08:13 BST CiteULike: dcastros Hummer http://www.citeulike.org/user/dcastro/author/Hummer CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/2782006 <i>Microwave Symposium Digest, 1988., IEEE MTT-S International (1988), pp. 963-966 vol.2.</i><br /><br />A description is presented of active antennas and arrays fabricated using microstrip patch antennas and Gunn diodes. Injection-locking experiments were carried out on these <e1>X</e1>-band antennas to achieve frequency coherency and to calculate the circuit <e1>Q</e1>-factor. An electronic tuning range of over 9% has been achieved for the single active patch element. A two-element active array was also developed. The output power levels from the two elements were combined in free space, resulting in higher power in the main beam. The tuning range was much narrower and the antenna pattern broke from a single beam into two separate beams as the DC bias voltage was varied. The breakup limits the practical tuning range Microstrip active antennas and arrays KA Hummer K Chang doi:10.1109/MWSYM.1988.22191 Microwave Symposium Digest, 1988., IEEE MTT-S International (1988), pp. 963-966 vol.2. 2008-05-09T23:43:10-00:00 1988 Microwave Symposium Digest, 1988., IEEE MTT-S International 963 966 vol.2 active antenna array microstrip http://www.citeulike.org/user/dcastro/article/2762265 <i>Electronics Letters, Vol. 24, No. 21. (1988), pp. 1347-1348.</i><br /><br />An FET source has been integrated with a microstrip patch antenna to form an active radiating module. The patch antenna serves both as a radiating element and a resonator in the feedback loop for the FET oscillator. Power output of 17 mW was achieved at 5.7 GHz Active radiating element using FET source integrated with microstrip patch antenna K Chang KA Hummer GK Gopalakrishnan Electronics Letters, Vol. 24, No. 21. (1988), pp. 1347-1348. 2008-05-06T18:38:41-00:00 1988 Electronics Letters 24 21 1347 1348 active antenna fet microstrip patch http://www.citeulike.org/user/dcastro/article/2762107 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 37, No. 7. (1989), pp. 1078-1084.</i><br /><br />Two types of active antenna elements have been studied experimentally. One type uses a microstrip antenna with an active device mounted directly on the antenna. The other uses an active device coupled to a microstrip patch antenna through an aperture. Microstrip active antenna elements and two-element arrays have been demonstrated for both types of circuits. Injection locking of the antenna elements has been achieved through space and mutual coupling. The circuit <e1>Q</e1> factor was calculated based on the locking gain and the locking bandwidth. The power output from two elements has been successfully combined in free space with a combining efficiency of over 90%. For a single active antenna with a Gunn diode mounted directly on the patch, an electronic tuning range exceeding 9% has been achieved by varying the DC bias. The results should have many applications in low-cost active arrays, active transmitters, and spatial power combiners Experiments on injection locking of active antenna elements for active phased arrays and spatial power combiners K Chang KA Hummer JL Klein doi:10.1109/22.24551 Microwave Theory and Techniques, IEEE Transactions on, Vol. 37, No. 7. (1989), pp. 1078-1084. 2008-05-06T17:19:30-00:00 1989 Microwave Theory and Techniques, IEEE Transactions on 37 7 1078 1084 active antenna array phased