Rx Frequency Research Articles

Frequency-Selective Beam-Shaping Technique to Provide Equal Beam Coverage Using Reflectarray Antennas for Dual-Band Multispot Satellites

In this communication, a simple technique is presented for transmit/receive (Tx/Rx) reflectarrays in the Ka-band to improve the shaping of the Rx beams without altering the performance in Tx, with application to geostationary satellite communications. The technique is based on the introduction of a controlled phase noise in the reflected field at Rx frequencies by a 180° phase reversal gradually introduced in some reflectarray cells randomly distributed on the antenna. Simulations of a 1.8 m parabolic reflectarray at 19.7 and 29.5 GHz show a reduction of 2.6 dB in the roll-off factor at 29.5 GHz, with also lower sidelobe levels. The proposed solution offers a large flexibility to shape the beams by a simple method with a low computational cost that does not increase the manufacturing complexity and costs of the antenna.

An S-Band-Receiving Phased-Array Antenna with a Phase-Deviation-Minimized Calibration Method for LEO Satellite Ground Station Applications

This study presents a new S-band-receiving phased-array antenna with a phase-deviation-minimized calibration method for the ground station of a low Earth orbit (LEO) satellite. The proposed antenna consists of 16 subarrays, 16 beamforming receiving RF modules (BF-RFMs), a power/control board, and a 16-way feed network. The subarray was achieved by joining two 8 × 1 arrays with a two-way power combiner. The 16-element antenna subarrays showed a gain of 16.1 dBi and a reflection coefficient of less than −10 dB from 2.12 GHz to 2.45 GHz. The BF-RFM, which consists of three low-noise amplifiers (LNAs), a power combiner, a phase shifter, and a digital attenuator, was designed and fabricated. The BF-RFMs were provided by the power/control board and showed a gain of 30.8 ± 0.8 dB, an amplitude root-mean-square (RMS) error from 0.25 dB to 0.28 dB, and a phase RMS error from 1.8° to 2.5° over the Rx frequency range. The arrangement procedures of the 16 BF-RFMs are presented to increase beam pointing accuracy at the desired angle. A commercial 16-way feed network was employed to combine all the output ports of the 16 BF-RFMs. The assembled antenna, which has dimensions of 1.58 m × 1.58 m × 0.2 m, was measured by partial and full scans in the near-field scanning system. The back-projected algorithm was employed to calibrate the antenna’s gain patterns in the partial scan. The implemented phased-array antenna had a gain greater than 28.14 dBi, sidelobe levels less than −17.1 dB, and beam pointing errors less than 0.07° over the beam pointing angle of −20~+20°. Based on the implemented antenna system, we conducted a field test using KOMPSAT-5, which is actually operating in South Korea, in order to verify the performance of the low Earth orbit (LEO) satellite ground station system.

A Compact Low-Loss High-Selectivity Excellent-Isolation FBAR Duplexer Integrated Chip for LTE Band-3 Industrial Applications

This brief presents a complete design flow for a compact low-loss high-selectivity excellent-isolation LTE Band3 (B3) duplexer (TX: 1710 MHz-1785 MHz, RX: 1805 MHz-1880 MHz). The proposed chip duplexer is based on the thin film bulk acoustic resonator (FBAR). In addition to the general design method, the effects of temperature drift, resonator performance distribution on wafer, the quality factor of inductance, device yield, and dissipated power density distribution on the design flow are described. These aspects are of great significance for the batch production of FBAR duplexers in the industry. Samples that pass the above industrial process are selected for testing. Measured results show reasonable consistency with the co-simulation results. 1.2/1.0-dB minimum IL in TX /RX band, 20-dB rejection in 3.5 GHz (second harmonic of TX), and more than 50 dB isolation in both TX and RX frequency are achieved with less massload simultaneously.

Single Waveguide Feed Omnidirectional and Circularly Polarized Transceiver Waveguide Slot Antenna for Satellite Communication Applications

In this study, an omnidirectional and circularly polarized transceiver antenna, which can be used in simultaneous operations over transmit (TX) and receive (RX) channels for telemetry, tracking, and command (TTC) applications on the space segment of satellite communication, is proposed. The radiation and feed parts of the antenna consist of waveguide structures for high power necessity in transmit (telemetry) section. The radiation part includes two different sections of rotationally symmetric slotted arrays on circular waveguide, and radially outward metallic disks to improve omnidirectionality and circular polarization. The feed part contains a dual-band mod converter from rectangular TE10 mode to circular TM01 mode for symmetric field excitation over slots where the input of the converter is the standard rectangular waveguide. The design, simulation, and measurement results of the antenna are shown over a 3D printed prototype at Ku-band with center frequencies of 12 GHz and 14.25 GHz for TX and RX, respectively. With thin slots in telemetry section and thick slots in telecommand section, measured bandwidths for TX and RX frequencies are obtained approximately as 200 and 450 MHz, respectively. While TX band with maximum 3 dB gain variation over azimuth, maximum 3 dB axial ratio and minimum −3 dBi gain over 70° elevation beamwidth has relatively better performances at the expense of narrow bandwidth, RX band has maximum 3.5 dB gain variation over azimuth, maximum 4 dB axial ratio and minimum −6 dBi gain over 55° elevation beamwidth at the expense of wide bandwidth.

Realization of In-Band Full-Duplex Operation at 300 and 4.2 K Using Bilateral Single-Sideband Frequency Conversion

CMOS-integrated in-band full-duplex (IBFD) operation in wireless links and cryogenic quantum platforms was previously enabled by magnetic-free circulators using the phase non-reciprocity from spatial-temporal modulation. In this article, we present an alternative and simple integrated circuit scheme, which not only realizes non-reciprocal signal flows required for IBFD operations but also improves the isolation performance by completely eliminating any chip-level transmit (TX)-to-receive (RX) coupling. The above functions are enabled by performing a direction/frequency-independent, single-sideband down-conversion to the counter-propagating TX and RX signals, which creates opposite deviations of on-chip TX and RX frequencies with respect to the antenna (ANT) frequency. Such a principle also broadens the isolation bandwidth and enables integrated receiver down-mixing function. As a proof-of-concept, a 3.4-4.6-GHz (30% fractional bandwidth) IBFD interface is implemented using a 65-nm bulk CMOS technology. The measured TX-to-RX isolation of the circuit is 32-51 dB at 300 K, and 14-29 dB at 4.2 K. The measured TX-to-ANT and ANT-to-RX insertion losses are 3.0 and 3.2 dB at 300 K, and 1.9 and 2.0 dB at 4.2 K. At 300 K, the measured TX-to-ANT and ANT-to-RX IIP3 are 29.5 and 27.6 dBm, respectively. The IBFD core of the chip occupies an area of 0.27 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and has a dc power (nominally consumed in an on-chip modulation clock generator) of 48 mW at 300 K and 42.6 mW at 4.2 K.

Harmonic Reflection Amplifier for Widespread Backscatter Internet-of-Things

The highly power-efficient backscattering communication scheme holds solid potentials to lead the Internet of Things technologies. However, the asymmetric radio frontend architectures that ensure cheap and pervasive communicating things and tags at one end of the link, overburden the other end of the link (“reader”) with complicated and expensive hardware. This turns out to prevent the integration of the technology in the wide spectrum of consumer electronic devices (e.g. RF smartphone platforms). By separating TX and RX frequency bands, the harmonic backscattering scheme drastically loosens the technological constraints toward integration. We propose here the use of a single tunnel diode to build a harmonic reflection amplifier (HRA), using the nonlinear behavior of the negative differential resistance region to both generate harmonics and amplify the signals. The circuit also behaves like a common backscatter, with the same-frequency backscattering modulation for operation with legacy readers. Operating below 150 mV, the HRA drains 144-μW dc power with a measured positive conversion gain of 18 dB.

Dual-Band Reflectarray to Generate Two Spaced Beams in Orthogonal Circular Polarization by Variable Rotation Technique

This contribution describes the design of a reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at transmit (Tx) and receive (Rx) frequencies in the Ka band. The discrimination in CP is achieved by the variable rotation technique (VRT), whose dual band operation is validated for the first time by the manufacture and measurement of a 25 cm × 25 cm reflectarray demonstrator. Moreover, an optimization procedure has been implemented to improve the narrowband performance of the VRT (which leads to high cross-polar levels when the VRT is applied). The reflectarray prototype has been designed to deviate by ±5° the beams radiated by a dual-CP feed-horn at Tx and Rx frequencies in the Ka band (20/30 GHz). The results are satisfactory and validate the concept of generating two spaced beams in orthogonal CP and dual band by the VRT with a single feed. This concept can be suitable for multiple spot satellites in the Ka band, enabling a reduction in the number of antennas and feeds needed to provide the multispot coverage.

Non-dimensional analysis of depth, orientation, and alignment in acoustic power transfer systems

Acoustic power transfer systems are typically comprised of an electrical source, acoustic transmitter (TX), medium through which the acoustic waves propagate, acoustic receiver (RX) and an electrical load. The voltage generated across and power delivered to the load from the TX is a function of RX position (depth, orientation, and alignment relative to the TX), frequency, TX and RX diameter, and source and load impedance. In applications where the RX position is not fixed, such as in implantable medical devices, slight disturbances in RX position can result in a severe reduction in load voltage and power. Therefore, the sensitivity of voltage and power as a function of RX position is crucial to system design. This paper presents an analysis of the load voltage and power as a function of RX depth, orientation, alignment, frequency, RX and TX diameter, and load impedance. Design graphs are developed and presented as a means of visualizing the sensitivity of voltage and power to system parameters. Non-dimensional design graphs are then generated to broaden the applicability of simulation results.

A SAW-Less Tunable RF Front End for FDD and IBFD Combining an Electrical-Balance Duplexer and a Switched-&lt;italic&gt;LC&lt;/italic&gt; N-Path LNA

This paper proposes a surface-acoustic wave (SAW)-less tunable RF front end (RF-FE) using an electrical-balance duplexer (EBD) integrated with a switched-LC N-path low-noise amplifier (LNA). The EBD cancels the transmitter–receiver (TX–RX) leakage at the RX frequency by dynamically optimizing the balance of a hybrid transformer, which enables in-band full-duplex (IBFD) operation. A transconductor-based LNA in parallel with a switched-LC N-path network creates input and output notches to reject TX leakage for frequency-division duplexing (FDD) operation. The LNA’s signal-handling capability is enhanced via optimum switch biasing. Fabricated in 0.18- $\mu \text{m}$ SOI CMOS, the RF-FE offers >50-dB tunable rejection from the TX port to LNA output at both TX and RX frequencies, for all 3GPP bands from 0.7 to 1 GHz (i.e., FDD case). It is the first tunable RF-FE including an LNA that achieves +70-dBm TX-path IIP3, and +30-dBm in-band TX power while cancelling the self-interference by >50 dB (i.e., IBFD case). The RF-FE consumes 62.5 mW at 1 GHz with 11.7-dB RX cascaded NF, 3.6-dB TX insertion loss, and 9.62 mm2 active area.

Novel Inductive Wireless Power Transfer Uplink Utilizing Rectifier Third-Order Nonlinearity

This paper proposes a new approach for inductive wireless power transfer (IWPT) tag-to-reader communication. A new technique to achieve transmitter/receiver (Tx/Rx) frequency separation is demonstrated. A two-tone Tx is adopted at the reader, and the third-order intermodulation (IM3) frequency generated by the tag rectifier nonlinearity is used as the Rx carrier, which is modulated by a baseband signal sent by the tag. The uplink signal at the IM3 frequency can be picked up by the reader coil. The IWPT impedance matching networks for both the reader and the tag coil can be reused efficiently, since the IM3 frequency at 5.06 GHz is close to the Tx fundamental frequencies at 4.94 and 5 GHz. Due to the Tx/Rx frequency separation, the Tx-to-Rx leakage at the Rx frequency can be suppressed by external filters to improve the Rx signal-to-noise ratio (SNR). The proposed technique is implemented within a 5-GHz IWPT system, and a tiny CMOS tag with a coil size of only 0.01 mm2 is used. This paper also implements conventional direct and intermediate frequency-based backscattering uplinks for comparison, and the proposed IM3 uplink is able to improve the Rx SNR by more than 20 dB. The achieved uplink data rate (100 kb/s) is also higher than the published work (20 kb/s) that adopted the conventional backscattering method.

A Comparative Analysis of CMUT Receiving Architectures for the Design Optimization of Integrated Transceiver Front Ends.

A formal comparison between fundamental RX amplifier configurations for capacitive micromachined ultrasonic transducers (CMUTs) is proposed in this paper. The impact on both RX and the pulse-echo frequency response and on the output SNR is thoroughly analyzed and discussed. It is shown that the resistive-feedback amplifier yields a bandpass RX frequency response, while both open-loop voltage and capacitive-feedback amplifiers exhibit a low-pass frequency response. For a given power dissipation, it is formally proved that a capacitive-feedback amplifier provides a remarkable SNR improvement against the commonly adopted resistive feedback stage, achieved at the expense of a reduced pulse-echo center frequency, making its use convenient in low-frequency and midfrequency ultrasound imaging applications. The advantage mostly comes from a much lower noise contributed by the active devices, especially with low- Q , broadband transducers. The results of the analysis are applied to the design of a CMUT front end in BIPOLAR-CMOS-DMOS Silicon-on-Insulator technology operating at 10-MHz center frequency. It comprises a low-power RX amplifier, a high-voltage Transmission/Reception switch, and a 100-V TX driver. Extensive electrical characterization, pulse-echo measurements, and imaging results are shown. Compared with previously reported CMUT front ends, this transceiver demonstrates the highest dynamic range and state-of-the-art noise performance with an RX amplifier power dissipation of 1 mW.

Inductive Power Transfer Uplink Using Rectifier Second-Order Nonlinearity

This work introduces two new uplink schemes for inductive wireless power transfer (IWPT) system with significant rejection on the Tx-to-Rx interference and noise. The second-order nonlinearity of the diode rectifier on the tag (target) is utilized to generate a new frequency component at the second-harmonic (SH) frequency of a continuous-wave (CW) Tx or at the second-order intermodulation (IM2) frequency of the a two-tone Tx. The two new frequencies are distant from the Tx fundamental frequency used for wireless powering, so the undesired Tx interference/noise at the Rx frequency can be filtered at the Tx output without compromising the wireless power transfer. The tag-to-reader uplink can be performed at the new Rx frequencies. PCB implementations for the SH and IM2 uplink are demonstrated with the signal-to-blocker ratio (SBR) largely improved compared to the conventional backscattering uplink. Although the Rx signal is weaker at the new uplink frequencies, the signal-to-noise ratio (SNR) of the SH uplink can out-perform the SNR of the backscattering uplink when a high-power Tx is required. The comparison between the SH, IM2, and the backscattering uplink is provided, in terms of SBR, SNR, and the power conversion efficiency.

Association between Sport Performance and Alpha-Actinin-3 Gene R577X Polymorphism

Physical performance has been associated with many gene variants including the alpha-actinin-3 gene (ACTN3) R577X polymorphism. The purpose of the present study is to investigate whether there is an association between sport performance of Turkish elite athletes and alpha-actinin-3 gene R577X polymorphism. A total of 300 individuals (150 elite athletes and 150 sedentary individuals) participated in the study voluntarily. A 291-bp long region spanning the R577X polymorphic site of the alpha-actinin-3 gene was amplified and tested with polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) method. The statistical analyses were done by using SPSS 15.0 package program. Although, no significant difference was found between the distributions of the three genotypes of elite athletes and sedentary individuals, the frequency of XX genotype in sedentary individuals was lower than that of the elite athletes (p>0.05). The RX and XX frequencies were significantly different (P<0.05) between the two groups. To the best of the researchers’ knowledge, there are no reports that examined the ACTN3 polymorphism in the Athletes who live in Black sea region of Turkey

Association between Sport Performance and Alpha-Actinin-3 Gene R577X Polymorphism

KEYWORDS ACTN3. SNP. Turkey. Athletic performance. Association. Elite Athletes ABSTRACT Physical performance has been associated with many gene variants including the alpha-actinin-3 gene (ACTN3) R577X polymorphism. The purpose of the present study is to investigate whether there is an association between sport performance of Turkish elite athletes and alpha-actinin-3 gene R577X polymorphism. A total of 300 individuals (150 elite athletes and 150 sedentary individuals) participated in the study voluntarily. A 291-bp long region spanning the R577X polymorphic site of the alpha-actinin-3 gene was amplified and tested with polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) method. The statistical analyses were done by using SPSS 15.0 package program. Although, no significant difference was found between the distributions of the three genotypes of elite athletes and sedentary individuals, the frequency of XX genotype in sedentary individuals was lower than that of the elite athletes (p>0.05). The RX and XX frequencies were significantly different (P<0.05) between the two groups. To the best of the researchers' knowledge, there are no reports that examined the ACTN3 polymorphism in the Athletes who live in Black sea region of Turkey

A Fully Integrated 60-GHz CMOS Transceiver Chipset Based on WiGig/IEEE 802.11ad With Built-In Self Calibration for Mobile Usage

This paper presents a fully integrated transceiver chipset based on the WiGig/IEEE 802.11ad standard targeting mobile usage. The chipset is developed for single-carrier (SC) modulation, which is suitable for reduced power consumption. However, the SC modulation is sensitive to in-band amplitude variations, mainly made worse by the gain variations of analog circuits and multipath delay spread. In order to compensate for these gain variations, the proposed chipset employs built-in TX in-band calibration and an RX frequency domain equalizer (FDE). The proposed techniques relax the requirement for high speed analog circuits, leading to less power consumption while minimizing the increase of hardware size. The test chip achieves 1.8 Gb/s MAC throughput for up to 40 cm and 1.5 Gb/s for up to 1 m while consuming 788 mW in TX and 984 mW in RX mode.

Loss of Response Five to Ten Years after Starting Infliximab

Purpose: Infliximab (IFX) is a very effective therapy for inflammatory bowel disease (IBD), but many patients lose response during the first few years of therapy. There is little data regarding the loss of response (LOR) after five years of treatment (Rx). The aim is to evaluate LOR and side effects (SE) to IFX after five years of Rx in our pediatric and young adult IBD population. Methods: We conducted a retrospective chart review of all the patients who received IFX in our practice. We collected clinical data and especially the reasons for modifying or stopping Rx. Results: Over a 12-year period, we treated 252 IBD patients with IFX (232 had Crohn's disease, 18 had ulcerative colitis and two had undifferentiated colitis). There were 156 males and 96 females, with an age range at the onset of Rx of ten months to 21 years, with a mean of 11.5 years. 124 were treated for less than two years, 63 between two and five years, and 47 over five years (including three for over ten years). We had incomplete information on 18. Of the 63 who received the IFX for 2 to 5 years, 34 (54%) are still on Rx and 29 (46%) are off Rx. The dose or the Rx frequency increased in 14 of the 34 still receiving IFX (41%) and 13 of the 29 that stopped (45%). The reason for stopping the Rx was LOR in 18 (8 after the dosage was increased), an acute infusion reaction in 3, patients preference in 2, remission in 2, intra abdominal carcinoma in 1, high-grade cervical dysplasia in 1, surgery in 1 and was unknown in 1. Of the 47 who received IFX for more than 5 years, 36 (76.5%) are still on Rx and 11 (23.5%) are off Rx. The dose or the Rx frequency was increased in 20 of the 36 still receiving Rx (55.5%) and 5 of the 11 that stopped Rx (45.4%). The reasons for stopping Rx was LOR in 6 (3 after the dose was increased), an acute infusion reaction in 1,delayed infusion reaction in1, peripheral neuropathy in 1 and patient preference in 2. There were 7 major complications: 3 malignancies, 2 cervical dysplasias, one peripheral neuropathy and one developed pancreatitis followed by chronic renal failure. Three died, one with intra abdominal carcinoma, one who had a liver transplant and then developed PTLD (while off IFX) and one from a surgical complication. Conclusion: Our data shows loss of response to Infliximab may occur after more than five years of continuous Infliximab treatment. In addition, a significant number of our patients required an increase in dose or frequency of treatment.Table: Table. Reasons of ending therapy

A Wideband Receiver With Resonant Multi-Phase LO and Current Reuse Harmonic Rejection Baseband

In this work we present an architecture for a low power SDR which draws on techniques from both narrowband low power radios and recent work in SDRs. The receiver consists of a wide tuning-range passive mixer, driven with resonant non-overlapping LO drive combined with a noise-power optimized multi-path baseband amplifier. LO generation circuitry drives the mixer with an 8-phase, 12.5% duty cycle LO, but does so directly from complementary LC-tank VCOs in order to resonate out the gate capacitance of the mixer. A capacitor sharing technique on the baseband side of the mixer doubles the RX frequency range of the 8-phase clock at no added cost in power or performance, while achieving a NF as low as 7 dB. The 1.8 mW low noise baseband amplifier reuses the bias current of its four input channels while rejecting the 3rd/5th harmonics by >34 dB. The receiver consumes 10–12 mW (including VCOs, pulse generation and baseband) over a frequency range of 0.7–3.2 GHz with a 1.3 V supply.

Radiofrequency Exposure in Greek Indoor Environments

This is the first measurement campaign that takes place in Greece in order to assess the exposure levels in different microenvironments (offices, bedrooms, living rooms, schools). Due to the exponential growth in the use of wireless network devices, the aim of this work was to perform indoor measurements with the use of personal dosimeters. The measurement period was 3 d in each of the 40 different locations that were selected, both in the urban and suburban area of Thessaloniki, the second largest city of Greece. The measurements took place from 23 July 2010 to 19 January 2012. After processing the obtained data with the robust regression on order statistics (ROS) method, various statistical exposure quantities were calculated. Compared to similar measurement campaigns across Europe, a larger proportion of measurement data above the detection limit for specific frequency bands (at most 56% for the DCS Rx frequency band) was found. Furthermore, mean exposure levels in the mobile downlink frequency bands were higher than those in other studies (GSM Rx: 0.259 V m, DCS Rx: 0.131 V m, UMTS Rx: 0.12 V m), yet many times below the ICNIRP guidelines. On the other hand, maximum exposures were found to be of the same magnitude (GSM Rx: 0.38 V m, DCS Rx: 0.3 V m, UMTS Rx: 0.28 V m). These measurement results indicate that signals from mobile base stations are dominant in workplaces and schools, whereas wireless phones and computer networks play the leading role in home environments. While the former reach their maximum values during daytime, the latter have an observable increase in the evening after work hours.

Dual-Band Horn Array Design Using a Helical Exciter for Mobile Satellite Communication Terminals

A horn array antenna is proposed for dual-band and dual-polarization operation. The array is optimally designed to be used as a feeder in mobile satellite terminals with a hybrid antenna (HA) structure, but it can be also used independently as a phased array. The array has an oval-shaped rim to maximize the efficiency of the HA, and is composed of 20 horn elements in a hexagonal structure. The element has a horn radiator with a conical helix, which is placed inside the horn and excited by two ports for TX and RX at both ends. Therefore, the antenna can be simultaneously operational in the Ka-band TX and K-band RX frequency bands, using a compact structure providing left-hand circular polarization (LHCP) for TX and right-hand circular polarization (RHCP) for RX. The fabricated array is connected with active channel modules having 20 channels each for TX and RX, and it was experimented on within a beam scanning range of -5° to +5° in the azimuth and elevation directions using phase control of the ac tive channel module. The antenna has a minimum gain of 21.7 dBi over the TX band and 19.7 dBi over the RX band over the desired scan region. The maximum pointing error is about 0.32° and the pointing loss is approximately 1.3 dB. In addition to meeting the above RF requirements, the antenna is designed to meet environmental specifications such as wind loads as required for mobile terminals.

Integrated Leaky-Wave Antenna–Duplexer/Diplexer Using CRLH Uniform Ferrite-Loaded Open Waveguide

A novel integrated leaky-wave antenna-duplexer/diplexer, based on the CRLH uniform ferrite-loaded open radiating waveguide is introduced, demonstrated and characterized both numerically and experimentally. The duplexing operation, characterized by equal Tx and Rx frequencies, is performed directly within the antenna thanks to the non-reciprocity of the ferrite, thereby suppressing the need for a circulator external to the antenna. The diplexing function, where the Tx and Rx frequencies are different, is achieved by inclining the plane of the antenna structure with respect to the normal of the radiation direction. The duplexer may be seen as the particular case of the diplexer with an inclination angle of zero. Virtually unlimited Tx → Rx isolation is provided by the leaky-wave nature of the device, which avoids typical problems of demodulation and detection/ranging errors and possible destruction of the receiver. Another advantage of this duplexer/diplexer is the possibility to tune the operation frequency by the applied magnetic bias field, whereas such tuning is prevented both by the antenna and by the circulator in conventional designs. The fabricated prototype exhibits a gain of 2.3 dBi with isolation of more than 15 dB at all ports. The diplexing frequency range reaches 400 MHz.