Browsing by Author "Chang, Li-Han"

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A Ka-Band Scalable Hybrid Phased Array Based on Four-Element ICs
(2020-01-01)
Chu, Ching-Yun
;
Chen, Yuan-Pu
;
Gao, Jing-Zhi
;
Ke, Cheng-Yung
;
Chen, Yu-Wei
In this article, a scalable hybrid phased-array system is presented through synchronization, analog complex weighting, and digital beamforming of numerous fully integrated Ka-band four-receiver (RX)/four-transmitter (TX) phased-array transceiver integrated circuits (ICs). A 1.09-GHz clock synchronizes the local oscillator (LO) and a 50-MHz clock synchronizes analog-to-digital (A/D)/digital-to-analog (D/A) converters for all array elements. Phase shifting is first accomplished in the analog domain using optimal intermediate frequency (IF)/LO complex weighting and signal summing in the 4RX/4TX IC to reduce the number of signals by a factor of four, followed by A/D sampling and digital beamforming in field-programmable gate arrays (FPGAs) and central processing units (CPUs). Phase-shifting properties, programmable gain variations, and antenna patterns of each RTX channel are measured and tabulated to calculate the optimal channel weights. The long-term phase stability is enhanced through temperature control by monitoring all ICs' temperatures in real time and adaptively adjusting the duty cycle of the TX mode of each IC to limit instantaneous temperature variations to +/- 0.5 degrees C over each calibration session. This reduces random phase errors from 13.3 degrees to 4.8 degrees in the TX mode. After each Vivaldi antenna is located on a 2-D rectangular grid, an 8 x 4 subarray module with synchronized digital output is demonstrated. With the boresight pointing along the x-axis, the eight-element dimension pointing along the y-axis, and the four-element dimension pointing along the z-axis, this subarray steers radiation patterns with the E-field polarized to the y-axis between +/- 40 degrees in both azimuth and elevation with 13.4 degrees and 26.4 degrees measured 3-dB beamwidths, respectively.
An X-band Waveguide Jig for Pre-screening Testing of Fully-integrated Elementary Phased-array Transceiver Antenna-in-package
(2018-01-01)
Chang, Li-Han
;
Wang, Chien Cheng
;
Wu, Yue Ming
;
Chu, Ta-Shun
;
Wang, Yu-Jiu
A large 9-10 GHz tile-based scalable phased-array system (over 128 elements) is built by flip-chip bonding of elementary antenna-in-package (AiP) modules on a large interposer PCB. Each module has a top radiating surface and a bottom BGA bonding surface. Due to the strict spacing requirement of a phased-array system, rework of any failed modules from the interposer PCB is prone to create more damages to the system and is prohibited. It is necessary to have a reliable and Automatic Test Equipment (ATE)-compatible test procedures to pre-screen qualified elementary modules for bonding. However, conventional ATE-compatible test jig designs can neither receive radiation signals from antenna nor feed test signals into the antenna. In this paper, a waveguide jig for AiP pre-screening is proposed. This jig system consists of a WR-90 adapter, a horn antenna, a Torlon cap and socket with POGO pins, and a PCB to interface with ATE. To test AiP transmitter, controls and test signals are provided through PCB connectors, with radiation signals collected from the WR-90 adaptor. To test the AiP receiver, radiation signals are feeding through the WR-90 adaptor, and the receiver output signals are collected from the PCB connectors. To calibrate waveguide jig return loss, a set of AiP SOL modules are used to remove PCB and test fixture loss from the overall system loss. The waveguide jig achieves a flat simulated -2.4 dB from AiP antenna port to waveguide port from 8 to 12 GHz. This waveguide jig provides a fast and reliable approach to select qualified AiP for phased array system assemblies, and the final system-level over-the-air testing.