For miniaturization, rectangular waveguides with a reduced height are often required, along with a coaxial transition for signal launching. We present a simulation-based design of a broadband transition from a coaxial cable to a rectangular waveguide with the height(b)-to-width(a) ratio b/a ranging from 0.125 to 0.375. The proposed transition consists of a coaxial probe with a cylindrical head or a disk and two symmetrically placed tuning posts. To extend the operating frequency range, three sections of the rectangular waveguide are employed with properly chosen dimensions. Design examples are presented for the WR75 waveguide transition with a b/a of 0.125, 0.25, and 0.375, having a bandwidth of 83.4%, 92.7%, and 84.4%, respectively. Compared with previous works, our design offers the largest bandwidth in a right-angle coaxial-to-rectangular waveguide transition employing the aforementioned structure.

This paper introduces a design for a charge pump DC-DC boost regulator with an integrated low-voltage control circuit. With a charge pump and feedback circuits implemented in 0.35 µm CMOS technology, the proposed DC-DC boost regulator offers an efficient device solution for low-power applications. The proposed design employs an error amplifier, oscillator, and comparator in the control circuit which is designed with a supply voltage of 1.8–3.5 V and 2 MHz frequency. Stability is obtained via a pole-zero compensation in the feedback circuit. The charge pump regulator with four pump stages and the whole regulator circuit are analyzed using the Cadence simulation tool. Measurements of the fabricated 0.35 µm CMOS regulator show that the transient time of the error amplifier is controlled within 1.0 µsec and the output voltage is accurately controlled from 7.8 V to 9.4 V with 27–38 mV ripple and 4.5 mA maximum current.

The integrated DC–DC converter is appropriate for use in many domains, namely, display, cellular, and portable applications. This paper presents an integrated control circuit for a monolithic voltage mode DC–DC boost converter for display driver applications. The control circuits consist of a transconductance amplifier, a comparator, and an oscillator. The boost converter consists of an inductor, two MOSFET, and an output RC filter. The control circuits are designed for fast transient response and low output ripple. The transconductance amplifier, comparator, and oscillator in the control circuit are designed to operate at a supply voltage of 3.3 V and an operating frequency of 5.5 MHz. The transconductance amplifier consists of an operational amplifier and an RC filter in the feedback path. The RC filter has a pole with a sufficient phase margin for high stability. The control circuits are realized in a 0.35-μm CMOS process together with the DC–DC converter. The fabricated DC–DC converter was evaluated by experiment and simulation. Testing of the proposed control circuits shows that the output transient time can be controlled within 7 μs, and the output voltage is accurately controlled with a ripple ratio of 3%.

본 논문에서는 전파고도계 개발에 사용하기 위해 여러 가지 평탄면에서의 산란계수 측정결과를 제시하였다. 2x4 배열로 구성된 송신(Tx) 안테나와 수신(Rx) 안테나를 설계 제작하여 산란계수 측정에 사용하였다. 84cm 간격으로 배치된 Tx/Rx 안테나의 Tx 신호가 반사면에 입사된 후 Rx 안테나에서 수신되는 신호의 전력비를 회로망분석기로 측정하였다. 측정된 송수신 전력비를 레이더 방정식에 대입하여 평탄면의 산란계수를 산출하였다. 수직입사, 수평편파 45° 경사입사, 수직편파 45° 경사 입사인 경우의 산란계수를 측정하였다. 수직입사의 경우 산란계수는 반사면의 종류에 따라 0.38부터 7.33의 값을 가지며 45° 경사입사의 경우에는 산란계수가 이보다 훨씬 작은 값을 가짐을 확인하였다.