Hee Nam

Ku-band transition between microstrip and substrate integrated waveguide (SIW)

In this paper, a Ku-band planar transition between microstrip and substrate integrated waveguide at satellite communication band is discussed. The SIW is one of alternatives for packaging the microwave components on the same substrate. The transition structure suggested in this paper shows the insertion loss of 0.7 dB at 12 GHz including transmission line of full wavelength.

Iris waveguide bandpass filter using substrate integrated waveguide (SIW) for satellite communication

In this paper, an iris waveguide filter with substrate integrated waveguide (SIW) structure at satellite communication band is discussed. The SIW structure is realized by via-holes on the substrate and shows a possibility of integration with other circuits. The iris waveguide filter has the insertion loss of 3.36 dB, the return loss of about 20 dB, and bandwidth of 3 %. Also, the iris waveguide filter using SIW has a sharp skirt characteristic.

A novel compact folded dipole architecture for 2.45 GHz rectenna application

A compact folded dipole architecture and a related system design method for 2.45 GHz rectenna application is presented. It is shown that using this folded dipole structure, the traditional rectenna system design can be almost simplified to only a required antenna design. Simultaneously, the design cycle time will be much reduced. In addition, the proposed architecture is uni-planar, robust, and compact, which lead to an easy design and realization at the required frequency ranges with a very low cost. The proposed 2.45 GHz rectenna system is designed and measured for its microwave performances.

Design of a new K-band push-push oscillator improving output power

As the modern communication technologies have been developed enormously, the higher frequency signals are required for transmitting the larger amount of information. The push-push structure for designing oscillator is one of the many techniques, which is used for increasing the oscillation frequency. Basically, the push-push oscillator circuit configuration enhances the even mode harmonics, and suppresses the odd mode output signal. Therefore, it doubles the oscillating frequency so that higher oscillating frequencies can be obtained beyond the limitation caused by the cut-off frequency of an available three terminal active devices [1-2]. The dielectric resonator is widely used for these applications since it shows the high quality factor [3]. However, it has a three dimensional (3D) structure, and its size is bulky. Therefore, it is not suited for the MMIC and it is hard to implement the small-sized circuit. To overcome this problem, hairpin resonators with a planar structure have been suggested and developed in MMIC technologies [4-5]. To improve the output power of an oscillator, the push-push oscillator is implemented on the harmonic oscillator type transforming the conventional push-push oscillator. Since each oscillator is designed as a second harmonic oscillator, the output power and the suppression of the fundamental frequency component are improved.

Design of a 5.8 GHz Narrow Band-pass Filter with Second Harmonic Suppression Using the Open Stubs

In this paper, integration of bandstop filter with the flexible narrow bandwidth of bandpass filter with lambdag/2 open stubs by microstrip line on duroid substrate is presented. This kind of filter shows flexible bandwidth with variation of the position of the open stubs using the external quality factor, Qe without changing the impedance value at microwave range. On the other hand, by replacing the series quarter-wavelength connecting lines with the equivalent T-shaped line, one could have compact stub bandpass filter with second harmonic suppression. This filter shows the insertion loss of 1.2 dB and the return loss of 21.9 dB at the center frequency of 5.8 GHz.

TUNABLE BAND-PASS FILTER USING INTERDIGITAL CAPACITOR BY BARIUM STRONTIUM TITANATE (BST) THIN FILMS

ABSTRACT In this paper, new design method of a bandpass filter (BPF) using tapped-line structure is suggested on BST/MgO substrate. A tunable BPF with interdigital capacitor (IDC) using BST thin film is successfully demonstrated for the improved tunability characteristic. The center frequency of the tunable hair-pin BPF with IDC is moved from 6.08 GHz to 6.30 GHz at 50 V bias with 2% bandwidth.

Design of a new elliptic function filter using a double spiral resonator with zero order characteristic

In this paper, a new design of the advanced elliptic function RF/microwave filter is presented. This filter is designed with compact size using novel miniaturized resonators. This new type of filter includes zero order characteristic with double spiral resonator. The resonator shows sharp cut-off frequency response and possibility of size reduction. The elliptic function filter with only a pair of attenuation poles (i.e., Transmission Zeros) at finite frequencies shows much improved skirt characteristic selectively. The proposed filter has the bandwidth of 5 % and the center frequency of 9.2 GHz.

Spurious Suppressed Substrate Integrated Waveguide Bandpass Filter Using Stepped-Impedance Resonator

A spurious suppressed bandpass filter is proposed and discussed using the stepped impedance resonator(SIR) on a substrate-integrated waveguide(SIW) structure with a double-layer substrate. The second resonance of the fundamental TE10 mode can be controlled by adjusting the electrical length and impedance ratio of each SIR. The spurious suppressed SIW bandpass filter shows the measurement results of the insertion loss of 3.98 ㏈ and return loss of less than 11.58 ㏈ at the center frequency of 12 ㎓. Also, the second spurious frequency is improved to about 1.5?? compared with 1.33??.

A New Substrate Integrated Waveguide (SIW) Cavity Resonator with Reflective Characteristic

In this paper, the substrate integrated waveguide (SIW) cavity resonator is proposed. The coupling between SIW cavity and microstrip line is achieved by the electric field at the vertical center plane along the propagation direction. Unlike the conventional cavity coupling structure that shows absorption characteristics at the resonant frequency, it can be easily integrated into planar form. The cavity resonator shows a loaded Q-factor of 211 at 12 GHz.

Design of Compact Bandpass Filters with λg/4 Short Stubs Using Transmission Zero

In this paper, compact bandpass filters with λg/4 short stubs by microstrip line on duroid substrate are presented. This kind of filter shows flexible bandwidth with variation of the position of the short stub using the external quality factor, Qe without changing the impedance value at microwave. This filter provides compact design and sharp skirt characteristic by transmission-zero. The bandpass filters can be realized with wide (60 %) and narrow (10 %) bandwidth just by adjusting the position of the short stubs. They show the insertion losses of 0.5 dB and 1.5 dB, and the return losses of 10 dB and 13 dB at the center frequency of 2 GHz, respectively.