An approximate lumped‐parameter equivalent circuit model of the quasi‐lumped element resonator antenna array is presented. The array consists of six series resonant circuits of frequency‐independent elements, each with an interdigital finger capacitor (IDC), and shorted across by a parallel narrow strip inductor. Each resonator exhibits an aperture size of 0.207 λ _g × 0.2 λ _g at a centre frequency of 5.8 GHz, with entire array size of 2.857 λ _g × 1.07 λ _g . The resulting design is fed by a microstrip line and excited by a coaxial feed probe. A simple equivalent circuit model representing the six resonant circuits as well as the coaxial feed probe circuit, using the magnetic‐frill model approach but with the simplest uniform‐current model is described to predict the characteristics of the proposed resonator (and by extension, the proposed array), the effects of the coaxial probe and the microstrip feed line. Simulated data obtained from a full wave analysis using finite integration technique commercial solver is compared with the Agilent advanced design system results of the equivalent circuit. The derived equivalent circuit model was validated both analytically and by numerical simulations.

An X-band tunable microwave low-phase noise planar oscillator employing a novel-fed dielectric resonator (DR) with a single transistor has been investigated and realized. A ZrSnTi oxide composite ceramic-based DR with dielectric permittivity of 95 enclosed in a metallic cavity with an unloaded Q factor of 5,000 at 10 GHz is proposed. The resonant frequency affinity with respect to geometric parameters is established by using the compensation technique based on dual negative conductance feedback, the outputs of which are combined via a Wilkinson power divider (WPD). The feedback parallel-coupled DR oscillator is incorporated into a laminate microwave board using the photolithographic technique. The oscillator includes a pseudomorphic low noise amplifier based on a high-electron-mobility transistor. Hence, the proposed oscillator with mechanic tuning is measured, and the results show that DR resonates at TE_01δ mode with frequency of 10 GHz. The measured phase noise of the oscillator is –81.03 dBc/Hz at a 100 kHz offset.

The design of radio frequency (RF) energy harvesting using planar circular spiral inductor antenna is proposed. The purpose is to determine the feasibility to harvest power density produced by the proposed antenna. A single element circular spiral antenna was designed, and subsequently, a 2 × 1 array to enhance the gain. Being a circular spiral inductor, it has a good Q-factor, higher inductance per unit area, and compact capability. The entire structure was investigated using numerical solver such as finite integration technique (FIT) method and Agilent advance design system (ADS) software. Results show that 3.22 dBi gain for single antenna and 5.14 dBi gain for antenna array was achieved at a centre frequency of 520 MHz. The gain of the 2 × 1 antenna array increased to about 37.3% over the single element. There are noticed reasonable agreements between the simulated and measured result.