Gyu-Je Sung

Equivalent circuit design of multilayer parallel-coupled line filter

LTCC filters have been widely used for wireless LAN terminals. They generally adopt the multilayer structure. Some multilayer LTCC filters are made of symmetrical parallel-coupled lines and anti-symmetrical parallel-coupled lines to reduce the length of resonators. The equivalent circuit of parallel-coupled lines was analyzed and applied to bandpass filters using multilayer parallel-coupled line resonators. A three-pole bandpass filter with a center frequency of 2.45 GHz is designed by using the proposed equivalent circuit and the measured results have good agreement with the design results.

Broadband 90° phase shifter using two short stubs

A novel, simple and broadband 90° bit C-band phase shifter was proposed and fabricated by LTCC process. It is composed of an 180° transmission line and two 90° shorted transmission lines. Design equations for the proposed 90° bit phase shifter are derived by admittance parameter analyses. Based on the design equations, a broadband a 90° bit phase shifter with ±2° of phase deviation was designed and fabricated.

LTCC MLC Bandpass Filter Using λ/4 Hairpin Resonators for K-PCS

In this paper, a novel λ/4 hairpin resonator is proposed to reduce the size of resonators. A LTCC MLC bandpass filter is designed using the λ/4 hairpin resonators. The electromagnetic coupling structure between two planar resonators is analyzed. The equivalent circuit is derived to explain the behavior of the LTCC MLC bandpass filter using λ/4 hairpin resonators. A design procedure is also described. The simulated and measured results of 1.8Ghz band 2-pole bandpass filter are presented

Tunable band-stop filter with combined Right/Left-Handed Transmission Line

In this paper, a tunable band-stop filter based on Right-Handed Transmission Lines (RHTLs) of low-pass characteristics and Left-Handed Transmission Lines (LHTLs) of high-pass characteristics are developed. This filter consists of a parallel connection of the RHTLs and LHTLs. Varactor diodes and chip inductors are used to make the unit cells of RHTLs and LHTLs. The cut-off point of the RHTLs becomes the lower cutoff frequency of the band-stop filter and the LHTL becomes the upper cut-off frequency. Therefore, upper and lower cut-off frequencies of the proposed band-stop filter can be controlled by the voltages of the varactor diodes, individually, and it is easy to change the center frequency and the bandwidth. The measured results of the tunable band-stop filter show a minimum bandwidth at 85.8% and a maximum at 133% from a center frequency of 600MHz. While the minimum insertion losses at pass-band are −0.9dB.

COMPACT ULTRA-WIDEBAND BANDPASS FILTER WITH SHARP ATTENUATION USING MODIFIED COMPOSITE RIGHT/LEFT-HANDED TRANSMISSION LINES

In this paper, the characteristics of novel modifled composite right/left-handed (CRLH) transmission lines are discussed, and an ultra-wideband (UWB) bandpass fllter (BPF) using the modifled CRLH transmission lines is presented. Design formulas of a novel modifled CRLH unit cell are theoretically derived. Based on the design formulas, the UWB bandpass fllter with three unit cells is designed, fabricated, and measured. The measurement results show that the UWB bandpass fllter has an insertion loss of less than 1dB, bandwidths of 2:9 » 49GHz, and a rejection of greater than 50dB at 5.8GHz.

Equivalent Circuit Design of Broadband 90° Phase Shifter

A novel, simple and broadband phase shifter was proposed and fabricated by the LTCC process. It is composed of a transmission line between two shorted transmission lines. Design equations for the proposed phase shifter are derived by the method of admittance parameter analysis. Based on design equations, phase shifter was designed and fabricated to operate in the C-band with of phase deviation.

Tunable Bandstop Filter with Combined Right/Left-Handed Transmission Lines

A novel tunable bandstop filter was proposed. It is composed of a right-handed transmission line, which has lowpass characteristics, and a left-handed transmission line which has highpass characteristics. Dispersion relations for the unit cells of RHTL and LHTL were derived by the method of ABCD parameter analysis. Varactor diodes and chip inductors were used to make the unit cells of RHTL and LHTL. A tunable bandstop filter was designed and fabricated by the parallel connection of RHTL and LHTL. The measured results of the proposed tunable bandstop filter are agreed well with the simulated results.

Broadband 180/spl deg/ bit X-band phase shifter using parallel-coupled lines

A novel, simple and broadband 180deg; bit X-band phase shifter was proposed and fabricated in a standard micromachining process. It is composed of two 90deg parallel-coupled lines; one of which is shorted and the other is grounded. Design equations for the proposed 180deg bit phase shifter are derived by the method of even and odd mode analysis. Based on design equations, 180deg bit phase shifter was designed and fabricated to operate from 7 to 13 GHz with plusmn5deg of phase deviation

LTCC MLC bandpass filter using /spl lambda//4 hairpin resonators for K-PCS

In this paper, a novel /spl lambda//4 hairpin resonator is proposed to reduce the size of resonators. A LTCC MLC bandpass filter is designed using the /spl lambda//4 hairpin resonators. The electromagnetic coupling structure between two planar resonators is analyzed. The equivalent circuit is derived to explain the behavior of the LTCC MLC bandpass filter using /spl lambda//4 hairpin resonators. A design procedure is also described. The simulated and measured results of 1.8 GHz band 2-pole bandpass filter are presented.