Quasi-optical antenna array amplifiers

Abstract

Several quasi-optical transmission wave amplifiers are presented: (1 j a two-level power-combining PHEMT patch-antenna lens amplifier with 8 dB of absolute power gain at 9.7 GHz used for beamforming and beam-switching; (2) a saturated class-A polarization-preserving 24-MESFET patch array which produces 0.7 Watts at 10 GHz with 21 % power-added efficiency; and (3) an X-band 2stage low-noise CPW PHEMT amplifier cell using anti-resonant slot antennas with 21.7 dB active gain, 3.2 rlB noise figure and a 6 % 3-dB bandwidth.

Modeling and performance of a 100-element pHEMT grid amplifier

“…The minimum noise figure is 3 dB with 3 V bias. This is comparable to the noise figure measured in [4] and is a 4-dB improvement over the HBT grid reported in [9]. The predicted minimum noise figure is given by Fukui's equation [ 181 where the transistor source resistance R, is 4.7 R, the transistor gate resistance Rg is 2.4 R, and the stabilizing gate resistance RSt is 25 R. Assuming that the material parameter K is 5, Fmin = 1.6 dB.…”

“…Metal-strip polarizers provide independent tuning of the input and output circuits. Other types of quasi-optical amplifiers using patch antennas [2]- [4], back-to-back integrated horn antennas [SI, [ 6 ] , folded slot antennas [7], and probe antennas [8] have been demonstrated. The largest number of devices have been incorporated in a 100-element HBT grid amplifier [9].…”

Circuit model for coplanar-slotline tees

“…1, is proposed. In contrast to previous works [1]- [6], it studies a general case in which CPW's are asymmetric, air bridges are not connected, and the COM propagates along the CPW section. The model is based Publisher Item Identifier S 1051-8207(00)04883-2. on the separation of modes (slotline, CEM and COM) into different ports, and therefore it provides a quantitative analysis of mode conversion (from slotline mode to CEM and COM, and vice versa) when the CPW section is loaded with general slotterminating planar structures that present different responses to each mode.…”

“…1, in which either CPW slot is connected to a slotline. This transition is used in a number of circuits, such as slotline antennas [1]- [3], directional couplers [4], and hybrid rings and their applications (mixers and amplifiers [5]). …”

“…The model is based Publisher Item Identifier S 1051-8207(00)04883-2. on the separation of modes (slotline, CEM and COM) into different ports, and therefore it provides a quantitative analysis of mode conversion (from slotline mode to CEM and COM, and vice versa) when the CPW section is loaded with general slotterminating planar structures that present different responses to each mode. Transitions with air bridges at the CPW section, such as those presented in [1], [2], [5], and [6], can also be analyzed as a particular case. Validation of the model is achieved through its application to the analysis of the input reflection coefficient, from 45 MHz to 40 GHz, of an offset-fed slotline antenna.…”