A Reflection-Type Dual-Band Phase Shifter with an Independently Tunable Phase

This paper presents a design for a dual-band tunable phase shifter (PS) with independently controllable phase shifting between each operating frequency band. The proposed PS consists of a 3-dB hybrid coupler, in which the coupled and through ports terminate with the same two reflection loads. Each reflection load consists of a series of quarter-wavelength (λ/4) transmission lines, λ/4 shunt open stubs, and compensation elements at each operating frequency arm. In this design, a wide phase shifting range (PSR) is achievable at each operating frequency band (fL: lower frequency; fH: higher frequency) by compensating for the susceptance occurring at the co-operating frequency band caused by the λ/4 shunt open stub. The load of fL does not affect the load of fH and vice versa. The dual-band tunable PS was fabricated at fL = 1.88 GHz and fH = 2.44 GHz, and testing revealed that achieved a PSR of 114.1° with an in-band phase deviation (PD) of ± 8.43° at fL and a PSR of 114.0° ± 5.409° at fH over a 100 MHz bandwidth. In addition, the maximum insertion losses were smaller than 1.86 dB and 1.89 dB, while return losses were higher than 17.2 dB and 16.7 dB within each respective operating band.

High-Performance RF Balanced Microstrip Mixer Configuration for Cryogenic and Room Temperatures

A high-performance S-band down-conversion microstrip mixer, for operation from 77 K to 300 K, is described. The balanced mixer combines a 90 degree hybrid coupler, two Schottky diodes, a band pass filter, and a low pass filter. The coupler phase shift drastically improves noise rejection. The circuit was implemented according to the configuration obtained from extensive simulation results based on electromagnetic analysis. The experimental results agreed well with the simulation results, showing a maximum measured insertion loss of 0.4 dB at 2 GHz. The microstrip mixer can be easily adjusted to different frequency ranges, up to about 50 GHz, through the proper choice of microstrip configuration. This novel S-band cryogenic mixer, implemented without resorting to special components, shows a very high performance at liquid nitrogen temperatures, making this mixer very suitable for high-temperature superconductive applications, such as front-ends.

5G Millimeter-Wave Beamforming System using Substrate Integrated Waveguide

Beamforming is a key element of 5G that uses advanced antenna technologies to focus a wireless signal to a defined direction. Butler Matrix (BM) as a beamforming network is used to control the beam direction by utilizing the amplitude and the output phase. A particular technique for designing BM is through substrate integrated waveguide (SIW), which is used to realize the bilateral edge wall vias where the waveguide mode propagates through to support the current flow and reduce the loss of surface wave. Unlike conventional BM, the proposed design requires only hybrid couplers and phase shifter without any crossover. In this BM structure, the SIW hybrid coupler is designed, with two phase shifters of -90°, and one phase shifter of -180° to control the amplitude and phase shifting. This results in an optimized transmission amplitude and output phase difference. The BM also circumvents any crossover, to provide minimal losses. The hybrid coupler exhibits Sii and Sij characteristics at 28 GHz, with values of -27.35 dB for return loss, -3.9 dB for insertion loss, -3.2 dB for coupling, and -26.54 dB for the isolation. In the BM design, high transmission efficiency is observed where the return loss is less than -10 dB, while minimal transmission amplitudes are obtained within the values of ‒6 ± 3 dB. The three-port BM is designed using SIW with minimal loss and the phase difference at each respective output port of the BM shows values of 0°, -120°, and 120°. The three consecutive beams with the gains of 11.1 dBi for port 1 excitation, 9.06 dBi for port 2 excitation and 10.4 dBi for port 3 excitation is achieved when the antenna array is fed to the BM, and each of the radiated beams has beam angles of 0, -27 and 27 degrees.

PENGARUH PERUBAHAN DIMENSI TERHADAP NILAI ISOLASI PADA BRANCH LINE COUPLER

Luasnya perairan nasional menjadi tantangan tersendiri bagi pemerintah dalam upaya pengamanan wilayah laut dari tindakan pelanggaran hukum. Indonesia perlu mengawasi betul-betul wilayah yang paling rawan agar sumber daya ikan nasional bisa dinikmati oleh masyarakat. Caranya, pangkalan bagi kapal-kapal pengawas (KKP, Bakamla, TNI AL) perlu dibangun di wilayah tersebut. Salah satu upaya yang perlu dilakukan yaitu peningkatan pengawasan secara ketat pemerintah dengan cara meningkatkan keamanan sekaligus menyusun aturan yang tepat agar bisa mencegah terjadinya pelanggaran hukum. kemampuan TNI AL dan Polri untuk menjaga seluruh wilayah laut, maka mereka harus menggunakan radar pengawas pantai. Radar pulsa ini mempunyai gelombang elektromagnetik yang diputus secara berirama, dan hanya memiliki satu antena yang digunakan untuk mengirim dan menerima sinyal. Untuk mengirim dan menerima sinyal, radar ini membutuhkan pemisah yang disebut duplekser. Duplekser berfungsi untuk mengisolasi sinyal yang ditransmisikan dan sinyal yang diterima dan komponen utama dari duplexer adalah Branch-Line Hybrid Coupler. Coupler memiliki parameter yang menunjukkan kinerja seperti: Return Loss, Power Coupling, Insertion Loss dan nilai isolasi. Dalam penelitian ini dilakukan penelitian untuk mengetahui pengaruh perubahan dimensi terhadap nilai isolasi pada Branch line coupler. Isolasi sangat penting karena mempengaruhi kinerja duplekser. Nilai yang lebih kecil semakin baik kinerja duplekser tersebut. Penelitian ini dilakukan dengan memodifikasi panjang dan lebar saluran impedansi Coupler. Branch-Line Coupler dirancang dalam bentuk mikrostrip dan difabrikasi menggunakan substrat FR-4 yang memiliki konstanta dielektrik 4,6, tebal 1,3 mm, dan frekuensi operasi 3 GHz. Untuk mendapatkan nilai optimasi karakteristik isolasi, kanal impedansi harus dimodifikasi, yaitu panjang dan lebar seri lengan (Z0 = 50 ), panjang dan lebar seri lengan (Z0 = 35,35 ), dan panjang dan lebar lengan shunt (Z0 = 50 ). Hasil optimasi isolasi didapatkan -67.786 dB.

CP Antenna with 2 × 4 Hybrid Coupler for Wireless Sensing and Hybrid RF Solar Energy Harvesting

The main challenge faced by RF energy harvesting systems is to supply relatively small electrical power to wireless sensor devices using microwaves. The solution is to implement a new device in a circularly polarized rectenna with circular polarization sensitivity integrated with a thin-film solar cell. Its dual-feed antennas are connected to a 2 × 4 asymmetric hybrid coupler and a multi-stage voltage doubler rectifier circuit. This configuration has a 2 × 4 asymmetric hybrid coupler used to produce 4 outputs with a 90-degree waveform phase difference. The two ports can independently be connected to the wireless sensor circuit: radiofrequency harvesting of hybrid energy solar and information equipment can be carried out with these two antennas. The Dual-Feed circular patch antenna has a two-port bandwidth of 137 MHz below −15 dB and an axial ratio of less than 3 dB, with a center frequency of 2.4 GHz with directional radiation and a high gain of 8.23 dB. It can be sensitive to arbitrary polarization of the input voltage multiplier waveform to overcome uncertainty in empirical communication environments. A parallel structure is arranged with a thin film solar cell integration from the transmitter with an output voltage of 1.3297 V with a compact composition and RF energy. The importance of adopting a wireless sensor strategy with circular polarization sensitivity and integrated RF solar energy harvesting rather than a single source method makes this research a significant novelty by optimizing the analysis of multiple wireless sensor signal access.

Center-Slotted Wideband Hybrid 10 dB Coupler

In this paper, a wideband microstrip hybrid coupler designed, simulated, built and tested. These couplers have advantage of easy fabrication, lightweight and incorporation with other microwave devices and validated using 3D planar electromagnetic softwares like Sonnet Suites. The final design is composition of two parallel lines with symmetric slits and a center slot. Directional coupler is designed and simulated to operate in the frequency range from 1 GHz to 5 GHz with 2.4 Ghz coupling -10 dB return loss bandwidth between 1.6 - 4 GHz. The fabricated coupler shows good agreement between measured and simulated results with very low isolation characteristics. Four symmetric orthogonal U-Shaped structures at the center of the coupling region distinguishes the proposed design with other works. It makes significant improvement in calculation duration thereby achieving lower response latency and lowers the possible manufacturing errors compared with previously published similar works.

Dual-Band/Dual-Mode Rat-Race/Branch-Line Coupler Using Split Ring Resonators

A novel dual-band/dual-mode compact hybrid coupler which acts as a dual-band branch-line coupler at the lower band and as a rat-race coupler at the higher band is presented in this paper. One of the most interesting features of the proposed structure is that outputs of the proposed coupler in each mode of operation are on the same side. This unique design is implemented using artificial transmission lines (ATLs) based on open split ring resonators (OSRR). The low-cost miniaturized coupler could be operated as a dual-band 90° branch-line coupler at 3.3 and 3.85 GHz and 180° rat-race coupler at 5.3 GHz. The proposed coupler could be utilized in the antenna array feeding circuit to form the antenna beam. The structure’s analytical circuit design based on its equivalent circuit model is provided and verified by measurement results.