• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.39 no.3
• /
• pp.158-164
• /
• 2002

2-6 GHz digital phase shifter module has been designed and fabricated. For the broadband operation and performance, MMIC phase shifter chip for phase shifter module was designed and fabricated by using the reflection-type circuits with Lange coupler. The fabricated phase shifter module shows 6.1$^{\circ}$RMS phase error, 13.5 dB maximum insertion loss, and 8 dB and 10 dB input and output return losses, respectively. Computer controlled measurement systems are realized in order to get the measured data of 32 phase states. The RMS insertion phase error and the average insertion loss deviation among 8${\times}$8 modules for the phased-array system are less than ${\pm}$0.5$^{\circ}$and ${\pm}$0.5 dB, respectively. The size of fabricated phase shifter module is 45 ${\times}$ 22.5 ${\times}$60㎣.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.7
• /
• pp.734-740
• /
• 2003

In this paper, A Vector Modulator based a wideband analog phase shifter is realized with four P-I-N diode attenuators, an asymmetric coupled line coupler, a symmetric coupled line coupler, and a power combiner. Simple configuration to have advantages in cost, size, power, and the number of passive circuits is presented. The phase variation due to phase and amplitude error of a P-I-N diode attenuator is derived and used to optimize the overall circuit. The phase shifter shows a total phase shift of 360$^{\circ}$, a 8.2$^{\circ}$maximum phase error, and a 16${\pm}$2.5 dB insertion loss over the wide frequency range of 1 GHz to 3 GHz.

• Journal of electromagnetic engineering and science
• /
• v.3 no.1
• /
• pp.62-66
• /
• 2003

Novel coupled line phase shifters and its equivalent phase delay line for compact broadband phased array antennas are proposed. These phase control circuits are designed to be less complex, small size and to use a less number of active devices. The phase shifter is able to control a 120$^{\circ}$ phase shift continuously, and the phase delay line for a reference phase has a fixed 60$^{\circ}$ shifted phase. Both have the low phase error of less than $\pm$3.5$^{\circ}$ and the low gain variations of less than 1 ㏈ within the 300 MHz bandwidth. These proposed circuits are adequate to form the efficient beam-forming networks with compactness, broadband, less complexity, and low cost.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.10
• /
• pp.1071-1078
• /
• 2003

In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3${\times}$1 phased array antenna system has a compact size of 1.6 λ${\times}$ l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S$\_$11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29$^{\circ}$to +30$^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.6
• /
• pp.501-504
• /
• 2017

In this paper, a hybrid beamforming antenna system using broadband butler matrix and phase shifter is proposed. In the previous works, an $8{\times}8$ butler matrix is used to overcome a drawback of the $4{\times}4$ butler matrix based switched beamforming which provides only 4 beam patterns. However the $8{\times}8$ butler matrix should be designed on the bi-layered substrate using via holes due to its complex structure. It causes performance degradation. To overcome these problems, the proposed hybrid beamforming antenna system is designed on the single side of the substrate for simple structure. By addition of two phase shifter, it provide various beam patterns. The proposed antenna system provides more than 10 dBi radiation gain in the ${\pm}45^{\circ}$ scanning range by 16 input combinations.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.9
• /
• pp.392-397
• /
• 2003

Reflection type phase shifter with Lange coupler is widely used as a circuit topology to obtain phase shift in broadband operation. The phase shift of 33.75$^{\circ}$ at this type is achieved by simultaneously turning on both 11.25$^{\circ}$ and 22.5$^{\circ}$ . In order to improve the phase accuracy of 33.75$^{\circ}$, this paper proposes the additional circuit which is composed of a GaAs PIN diode and a reactive load. By utilizing MMIC technology. Over the 2-6 GHz band, the measured result of phase difference between the previous circuit and the proposed circuit shows average 4.7$^{\circ}$ on the basis of 33.75$^{\circ}$. Insertion loss and return loss are invariant in comparison with the previous circuit.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.5 no.1
• /
• pp.43-59
• /
• 2006

A compact and broadband $4\times1$ array antenna was developed for 3G smart antenna system testbed. The $4\times1$ uniform linear away antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% $(VSWR\leq1.5)$, 21.78% $(VSWR\leq2)$ with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.7 no.1
• /
• pp.41-58
• /
• 2007

A compact and broadband $4{\times}1$ array antenna was developed for 3G smart antenna system testbed. The $4{\times}1$ uniform linear array antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% ($VSWR{\leq}1.5$), 21.78% ($VSWR{\leq}2$) with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• 한국정보통신설비학회:학술대회논문집
• /
• 2006.08a
• /
• pp.15-18
• /
• 2006

We have proposed a broadband analog feedforward optical transmitter using a wideband $180^{\circ}$ hybrid coupler instead of conventional frequency-sensitive phase shifter with the narrow bandwidth property using a wideband $180^{\circ}$ hybrid coupler, the wide-band linearization technique enhances the linearity of the feedforward optical transmitter. In two-tone cases, the $3^{rd}-IMD$ products was enhanced more than 10 dB in 385 MHz range(1.375$\sim$l.76 GHz).

• ETRI Journal
• /
• v.37 no.1
• /
• pp.26-31
• /
• 2015

Axial-ratio (AR) bandwidth enhancement is achieved for a circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) using a wideband hybrid coupler (WHC) combined with dual probe feed. The presented WHC, comprised of a Wilkinson power divider and a wideband $90^{\circ}$ shifter, delivers good characteristics in terms of 3 dB power splitting and consistent $90^{\circ}$ (${\pm}5^{\circ}$) phase shifting over a wide bandwidth. In turn, the proposed CP DRA, for the employment of the WHC, in place of conventional designs, provides a significant enhancement on AR bandwidth and impedance matching. The antenna prototype with the WHC exhibits a 3 dB AR bandwidth of 48.66%, an impedance bandwidth of 52.5% for voltage standing wave ratio (VSWR) ${\leq}2$, and a bandwidth of 44.66% for a gain of no less than 3 dBi. Experiments demonstrate that the proposed WHC is suitable for broadband CP DRA design.