• ETRI Journal
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• v.41 no.6
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• pp.715-730
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• 2019

We propose a switched beam-forming antenna that satisfies not only ultra-wideband characteristics but also beam-forming in the WLAN frequency band using an ultra-wideband antenna and passive parasitic elements applying a broadband optimal reactance load algorithm. We design a power and phase estimation function and an error correction function by re-analyzing and normalizing all the components of the parasitic array using control system engineering. The proposed antenna is compared with an antenna with a pin diode and reactance load value, respectively. The pin diode is located between the passive parasitic elements and ground plane. An antenna beam can be formed in eight directions according to the pin diode ON (reflector)/OFF (director) state. The antenna with a reactance load value achieves a better VSWR and gain than the antenna with a pin diode. We confirm that a beam is formed in eight directions owing to the RF switch operation, and the measured peak gain is 7 dBi at 2.45 GHz and 10 dBi at 5.8 GHz.

• ETRI Journal
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• v.27 no.6
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• pp.788-797
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• 2005

This paper describes the design and realization of an extra high frequency band $8{\times}8$ microstrip Butler matrix. Operation at 36 GHz is achieved with a frequency bandwidth exceeding 400 MHz. The circuit is implemented on a bi-layer microstrip structure using conventional manufacturing processes. This planar implementation of a Butler matrix is a key component of a switched beam smart antenna with printed antenna elements integrated on-board. Conception details, simulation results, and measurements are also given for the components (hybrid couplers, cross-couplers, and vertical inter-connections) used to implement the matrix.