This paper presents a design for a monopulse reflector antenna with asymmetric beamwidths for radar applications at the Ku band. The proposed design features a rectangular waveguide monopulse feed and a truncated parabolic reflector. An array of four open-ended rectangular waveguides were employed to realize a compact monopulse feed. The reflector is cut in the H plane of the feed producing a wider beam in the azimuth plane. This type of pattern is useful in applications such as projectile tracking and airport surveillance. The design parameters for optimum performances are chosen at all stages of the design. The design and analysis have been carried out using the commercial simulation tool CST Studio Suite 2022. The directivity of the sum, elevation difference and azimuth difference channels of the reflector antenna are 32.1, 28.1, and 26.4 dB at 14 GHz; 30.9, 29, and 27.3 dB at 15 GHz; 31.7, 29.6, and 27.6 dB at 16 GHz; 31.6, 29.9, and 27.8 dB at 17 GHz.

Presented in this paper is a conceptual design by computer simulation of a monopulse reflector antenna with dual-circularly polarized sum patterns and linearly polarized azimuth and elevation difference patterns, which can be called a semi-dual polarized antenna. The proposed antenna consists of a five-element monopulse feed and a prime-focus parabolic reflector. The novelty of the proposed antenna is a monopulse feed consisting of a dual-circularly polarized square waveguide sum channel radiator and linearly polarized rectangular waveguide azimuth and elevation difference channel radiators. The separation of dual circular polarization is realized by a septum polarizer. The difference pattern is obtained by feeding two rectangular waveguides in opposite directions using a coaxial probe. The proposed monopulse feed geometry requires only two power combiners for a monopulse comparator network while providing dual-polarized performance comparable to the full dual-polarized sum and difference channel monopulse scheme. The concept of the proposed antenna is shown in a conceptual design by computer simulation. The monopulse feed is designed first, and then combined with a parabolic reflector. The designed monopulse reflector antenna operates at 14.5–16.0 GHz, and shows excellent sum and difference pattern characteristics: 36.1–36.7 dBc sum channel directivity with 0.65 dB boresight axial ratio and 32.6–32.9 dBi difference channel directivity with 1.56–1.66° crossover angle.

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%.

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.

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 presents a computer-simulation-based design of an in-line, coaxial-to-circular waveguide adapter for converting the coaxial transverse electromagnetic (TEM) mode to the circular waveguide TE₁₁ mode over more than a one-octave bandwidth. The proposed adapter consists of a coaxial-to-rectangular waveguide transformer employing a stepped-ridge converter and a rectangular-to-circular waveguide transformer employing a curved transition. The proposed adapter has been optimized using a commercial simulation tool. The dimensions of the designed adapter are given so that it can be verified by anyone who is interested. The designed adapter operates from 8.00 GHz to 22.95 GHz (2.87:1 bandwidth) with a reflection coefficient of less than −20 dB and a higher-order mode level of less than −25.0 dB.