Sean Ortiz

Analysis and measurement of hard horn feeds for the excitation of quasi-optical amplifiers

Measurement and analysis of hard horn feeds for excitation of quasi-optical amplifiers has been performed. A computer program based on the mode matching technique has been developed in order to determine the aperture field distribution for pyramidal hard horns. This program can be used to optimize a hard horns field distribution and bandwidth. Simulation and measurement results for a 31 GHz hard horn feed are presented.

A Ka-band power amplifier based on the traveling-wave power-dividing/combining slotted-waveguide circuit

An eight-device Ka-band solid-state power amplifier has been designed and fabricated using a traveling-wave power-dividing/combining technique. The low-profile slotted-waveguide structure employed in this design provides not only a high power-combining efficiency over a wide bandwidth, but also efficient heat sinking for the active devices. The measured maximum small-signal gain of the eight-device power amplifier is 19.4 dB at 34 GHz with a 3-dB bandwidth of 3.2 GHz (f/sub L/=31.8 GHz, f/sub H/=35 GHz). The measured maximum output power at 1-dB compression (P/sub out/ at 1 dB) from the power amplifier is 33 dBm (/spl sim/2 W) at 32.2 GHz, with a power-combining efficiency of 80%. Furthermore, performance degradation of this power amplifier due to device failures has also been simulated and measured.

A high-power Ka-band quasi-optical amplifier array

Results for a high-power Ka-band quasi-optical amplifier array are presented in this paper. The amplifier consists of a 45-element double-sided active array with a hard-horn feed. Excess heat is removed via a metal carrier integrated into the array with liquid cooling at the periphery. Each unit cell of the array consists of transmitting and receiving patch antennas, driver and power amplifier monolithic microwave integrated circuits on input and output layers, and a through-plate coaxial transition, which connects the input and output layers. An estimated 25 W is radiated when the amplifier is used as an antenna feed, otherwise 13 W is collected into waveguide. Experimental results and construction details are discussed.

Analysis and measurement of hard-horn feeds for the excitation of quasi-optical amplifiers

Measurement and analysis of hard horn feeds for excitation of quasi-optical amplifiers has been performed. A computer program based on the mode matching technique has been developed in order to determine the aperture field distribution for pyramidal hard horns. This program can be used to optimize a hard horns field distribution and bandwidth. Simulation and measurement results for a 31 GHz hard horn feed are presented.

A Ka-band power amplifier based on a low-profile slotted-waveguide power-combining/dividing circuit

In this paper, a Ka-band power amplifier based on a resonant slotted-waveguide-to-microstrip power-dividing/combining circuit is presented. The advantages of this structure are its low profile, ease of fabrication, as well as its potential for high power-combining efficiency. In addition, efficient heat sinking of monolithic microwave integrated circuit (MMIC) devices is achieved. A slotted-waveguide power amplifier using eight MMIC amplifiers was designed and fabricated. The measured power-combining efficiency at 33 GHz is 72%. In addition, simulation results predicting the performance degradation of the slotted-waveguide power amplifier due to multiple device failure are presented.

A 25 watt and 50 watt Ka-band quasi-optical amplifier

Results for a 25 Watt, 10 dB gain Ka-band Quasi-Optical (QO) amplifier array are presented in this paper. The amplifier consists of a 45-element two-sided active array with a hard-horn feed. Excess heat is removed via a metal carrier integrated into the array. Each unit-cell consists of patch antennas, cascaded MMIC amplifiers, and a through-plate coaxial transition. Performance and construction details are discussed. Preliminary data for a 98-element design are also included.

Global coupled EM-electrical-thermal simulation and experimental validation for a spatial power combining MMIC array

The first fully coupled electromagnetic-electro-thermal global simulation of a large microwave subsystem, here a whole spatial power combining MMIC array, is described. The modeling effort is supported by parallel developments in electro-optic and thermal measurement. The CAD tools and experimental characterisation described, provide a unique capability for the design of quasi-optical systems and for the exploration of the fundamental physics of spatial power combining devices.

A waveguide-based aperture-coupled patch amplifier array-full-wave system analysis and experimental validation

In this paper, the full-wave analysis and experimental verification of a waveguide-based aperture-coupled patch amplifier array are presented. The spatial power-combining amplifier array is modeled by the decomposition of the entire system into several electromagnetically coupled modules. This includes a method of moments integral equation formulation of the generalized scattering matrix (GSM) for an N-port waveguide-based patch-to-slot transition; a mode-matching analysis of the GSM for the receiving and transmitting rectangular waveguide tapers; and a finite-element analysis of the waveguide-to-microstrip line junctions. An overall response of the system is obtained by cascading GSMs of electromagnetic structures and the S-parameters of amplifier networks. Numerical and experimental results are presented for the single unit cell and 2/spl times/3 amplifier array operating at X-band. The results are shown for the rectangular aperture-coupled patch array, although the analysis is applicable to structures with arbitrarily shaped planar electric and magnetic surfaces.

A 4 watt Ka-band quasi-optical amplifier

This paper reports on demonstrated results for a 4 W, 16 dB gain Ka-band Quasi-Optical (QO) amplifier. This amplifier consists of a 13 element two-sided active array with a hard-horn feed. Excess heat is removed via a metal carrier integrated into the array. Each unit-cell consists of patch antennas, cascaded MMIC amplifiers and a unique through-thick-plate coupler. Performance and construction details are discussed. Preliminary results from a 45 element design are also included.

A perpendicular aperture-fed patch antenna for quasi-optical amplifier arrays

A feed structure for an aperture coupled patch antenna is analyzed for applications in quasi-optical power combining arrays. The antenna feed provides a means of separating the active components from the radiating elements using a brick approach employed in the construction of phased array antennas. Simulated results show the applicability of the feed at Ka-band. Furthermore, measured results, which verify simulations performed at X-band, are presented.